A Teemo rework I plead you all to look at (and RIOT to playtest <3)
Seeing as the new (sexy af) skin has caused a revival in Teemo play (myself included), I'd really like to take this opportunity to present a Teemo rework that, I think, fixes the "problem" that is Teemo.
THE "TEEMO PROBLEM"
Teemo is one of my favorite champions that I'm not allowed to play. He's a near-useless addition to a teamcomp in almost all situations, no matter how you slice it. He's incredibly fun to play, but the fact that once laning is over you're stuck a squishy mixture of DPS and burst (but not enough of either to warrant picking him for it), who's barely useful in a teamfight because he still needs peel and doesn't really know if he wants long fights or short ones.
This isn't to say he's a bad champion by any means. Rather, I believe he's a legitimately powerful champion. The problem is there's no reason to pick Teemo in any given game over any other given champion in the roles he can fill or in what he brings to the table. His iconic traits are his blind, his poisons, and his shrooms, and none provides enough worth to a team to justify him over any other champion who can fill the role he'd be in. Thus, we have a numerically strong champion with potentially powerful laning, who doesn't snowball exceptionally well (compared to pretty much any other assassin or DPS carry), who also doesn't have a reason to be picked.
Thus, the "Teemo Problem", and why people hate seeing Teemo on their team in blind/draft pick, and why people kick him from rooms in Team Builder. Nobody wants the champion on their side, and frankly (as someone who plays like 80% assassins) the other team usually is happy to see him on the other side because he's usually free assassin kills.
As such, the biggest thing Teemo needs is a defined role. A reason you'd pick him, and a goal in mind as a champion. Here is what I propose:
The most defining thing about Teemo, I think, is his map control via his shrooms, and his "unexpected damage" potential via his stealth nature and poisons. Taking those traits and emphasizing them provides the champion with a distinct purpose, that would also extend beyond laning and into the teamfight/roaming phases of the game.
Please, bear with me, it's a long read, and I understand if you have better things to do, but I hope you'll find it's worth it.
PROPOSED KIT CHANGES
As actual number values would undoubtedly need tweaked, I intend to provide only a few estimates, as what I'd like to sell people on is the concept behind the kit rather than numbers outright. I do, however, have "guesses" I'd like to share to provide an understanding of where I believe his power should be in this kit.
Q: His Q, at the moment, is a fairly-heavy nuke with a blind attached. While this is a key skill for Teemo (and I believe heavily ingrained in who the champion is now), I think having it be the only "raw burst" skill in his kit is a hindrance to his character. I propose that his Q have some of it's up front burst taken off, and in exchange have it provide a poison effect that causes Teemo's poisons to deal a percentage of the afflicted champion's missing health as magic damage. This damage would be heavily tied to his AP scaling, with almost no base value, to prevent bruiser or AD builds from abusing it. It also would only have one instance active at any time, meaning each poison wouldn't apply a separate missing %hp burn, but as long as they were poisoned from something, the burn would keep going. Q itself would apply the missing hp poison for 4 seconds.
W: Mostly remaining unchanged, the one difference being something I'd rather address in his R section (but could go here instead for leveling purposes)
E: Unchanged, with the exception of the DoT effect applying the new Q effect.
R: The shrooms are, frankly, the most iconic thing about Teemo. I feel as if playing them up in his kit is a strong solution to "The Teemo Problem". Firstly, the base damage would need nerfed somewhat. However, There are a few major changes I would make to how the shrooms function. There are 4 changes I have in mind:
--"Teemo gains a (large) X% move speed boost for (thinking 3) Y seconds while moving towards a champion afflicted by his poison shrooms"
The intent of this is to provide Teemo a distinct role as a "pick off" assassin. This gives him strength as a roaming threat, as well as a much stronger thematic tie-in, and cements a real play pattern. Teemo places a shroom (or minefield of them), and waits nearby for an enemy to step on it, at which point he leaps from hiding and picks them off. The problem, currently, is that in order to benefit from his passive attackspeed steroid, you have to almost be on top of his shroom to utilize the bonus. This way, Teemo can actually set "traps", and hunt people down, rather than people knowing "either he's right here where I'm standing or not around at all". The move speed boost could either be tied to his W rank or R rank, depending on how Riot would want him to progress through the game.
--"Stepping on Teemo's shrooms cause his poisons to shred X% (thinking 3.5%) of afflicted target's magic resistance each tick, up to a cap (thinking up to 24.5%) that persists as long as the enemy is suffering from one of Teemo's poisons."
This does several things for Teemo. First, combined with the addition of missing %hp damage on Q afflicted targets, solidifies him as a killer of frontline champions in a teamfight. Whereas, currently, in a teamfight Teemo serves little purpose beyond some standard DPS and a blind on an ADC, this provides him a distinct role: Hang back and shred their frontline champions, leading their team through minefields as able. Furthermore, this gives Teemo an ultimate your team wants for teamfights, as well as incentiving your team to utilize his minefields, even if he's not snowballing. Providing a shred effect on the enemy team allows a lot of "disengage and re-engage" potential, turning what looks like a lost fight into a winnable one should the enemy team follow you to a bad place.
The purpose of causing all his poisons to apply the shred effect is twofold: Firstly, Teemo's shroom poison lasts 4 seconds, meaning that a single shroom would shred 14% MR after it's final tick. For comparison, Karthus wall shreds 15% instantly and Kayle passive shreds 15% after 5 attacks. This caps out a single shroom at a shred effect that's by itself rather weak compared to other shreds, considering it needs 4 seconds to reach 14%. However, this allows for enemies to be punished more and more (and Teemo rewarded for intelligent placement) when they walk through an unchecked area or chase too hard (that 3rd shroom will hurt something fierce). The 2nd value is that having all Teemo's poisons apply the shred means that the shred is vastly more useful against whichever champion Teemo is concentrated on. A single champion suffering from shrooms poison, Q poison, and his E poison would increment 10.5% MR shred each second (3.5 from each poison), reaching the cap after the 3rd poison tick, making him rather capable 1 on 1.
--"Time until Teemo stores another shroom is decreased by X (thinking 0.5) seconds each second an enemy champion is poisoned by Teemo's abilities."
More interactive than simply a flat cooldown decrease, I feel this allows Teemo to place more shrooms without encouraging the passive play that is part of what makes the champion undesirable-for-buffs on Riot's end. This way, Teemo can create a more robust minefield, without not needing to work to achieve it.
-- Allow Teemo to "lob" shrooms. Increase their placement distance by somewhere between 70 and 100 units.
Understandably, Teemo's shrooms have a small placement range, in order to prevent them from being used as a reliable "poking" tool or to not care about where he places them. This change, however, I would make for a multitude of reasons. Firstly, it allows him to place shrooms over many of the walls he previously could not. Second, it allows him the freedom to place shrooms in more useful positions in a teamfight without going horrendously out of position to do so. Third, it allows him to be slightly less obvious about shroom placement while ducking in and out of sight when he's being chased. Obviously, you want a heavily restricted placement range (he should be rewarded for preemptively setting up an effective network, not placing on the fly cough Rek'sai cough), but this opens up some freedom to the ability's usage without fundamentally changing the shrooms use or granting too much effectiveness without proper setup. Plus, seeing as many times in a fight Teemo shrooms on top of himself before running away anyway, this just allows him a little more freedom about utilising them to escape.
As I stated before this large block about his shrooms, it would likely need to see some base damage nerfs to compensate for the added power. However, I strongly feel there is significant benefit to pushing his shrooms in this direction, for his identity as a character, his usefulness on a team, and his playstyle as a whole.
DAMAGE CHANGES
Granted, both his Q and R would need compensatory nerfs to their damage (DOT on shrooms and base nuke on Q, obviously), but not too hard. Damage Over Time effects have a bit of a wider berth with regards to their damage output, as there is a SIGNIFICANTLY higher window for reaction time, as you often have several seconds to do something about a slowburn damage source than, say, the up-front instadeath provided by most assassins (Leblanc for example). You obviously couldn't just add MR shred to his current shrooms and missing %hp poison to his current Q, but he really wouldn't need terribly high number reductions on either ability in order to remain balanced. The goal would be for his damage over the duration of an attack on a shroomed target to be higher than Live, but up front it'd be less. His poison durations are 4 seconds, and that's basically 4 chances to say "oh, Teemo's gonna kill me, i should pop heal/barrier/zhonyas/pots/whatever". His DOT can be higher than Live if his Q burst and base R damage are lowered a little bit.
I feel his R should do less damage on Live with a single shroom, but if a 2nd shroom is hit (or Teemo follows up) before the MR shred wears off, the net change in damage should be an increase from Live. My rough guess would be a drop to 160/260/365 base damage over 4 seconds (scalings unchanged) as opposed to current Live values of 200/325/450 over 4 seconds.
His Q still needs to be a decent poking/lasthitting tool, but I feel like lowering it's base damage to 65/110/140/175/200 and it's scaling to somewhere between 50 and 55% would be enough to justify the addition of a 1%+(1% per 140/135/130/125/115 AP) missing health poison effect addition. Currently, Live Q does 80/125/170/210/260 + 80% AP, for reference.
I could be way wrong, as I've not tested the math extensively or been able to test it in-game, but that's why I'm asking Riot to playtest this.
PLAYSTYLE, PURPOSE, REASON-TO-PICK
Ideally, this kit accomplishes a few things, and these are reasons I like it to be considered.
-First, his role as a character (and "class") is much more strongly defined. Teemo would excel at picking off enemy champions who wander off alone, following up on someone who steps on a shroom by bursting in with a large amount of move speed, Q'ing them and autoattacking a few times while they're blinded, and then running away and letting the poison do it's work (or leading them through more shrooms) before the enemy team can interfere. He'd be an excellent "pick off stragglers/lone roamers" assassin, in a similar style to what Kha'Zix is (supposed to be) good at, but with more prep work and more potential counterplay time.
-Second, his role in a teamfight is much more obvious. He's definitely an assassin, but rather than focusing on the "high-priority" targets, such as Marksmen and Mages, he'd primarily focus on taking out their frontline, especially fighters and bruisers. He'd be especially effective at ducking in and out of a fight and harassing their frontline, or stealthing in the back of the team before unexpectedly joining what the enemy team expected to be a 5v4. He'd be effective bait as a setup for a teamfight, harassing the enemy team into chasing him into an MR-shredding shroom or two and the rest of his team, before engaging with his backup for a much more deadly teamfight.
-Third, there's now a reason to pick Teemo. You pick him into an enemy teamcomp focused on abusing splitpush champions, as he wants to catch lone shroom-poppers, or a into an enemy teamcomp heavily emphasizing bulky, frontline fighters (nasus, vi, darius, etc), as he'd excel at messing up thoughtless engages or champions who go in too deep on your carries. When you'd have a Teemo on your team you'd now have a thing that Teemo provides better than other champions, which is not the case with Live Teemo.
-Lastly, Teemo's current playstyle is incredibly passive. He never really goes on the offensive, and it encourages a low-interaction playstyle and frankly a potentially very boring experience for both parties. This heavily enforces a much more interactive and aggressive playstyle on Teemo, which is better for the champion, the players, and (as Riot isn't a fan of non-interaction) the game as a whole.
WRAP UP AND THANK YOUS
I already have a bunch of ideas in mind to swing him to a more powerful or less powerful state were people to agree he'd be one or the other, but that's the base point I'd work with. Please, if this interested any of you forum-goers, I implore you to grace this rework idea with some upvotes and comments (admittedly I'd prefer civil, polite ones, even if you hate it). That goes for you Reds too, I'd love to hear some opinions.
Like I said, PLEASE try to not focus on the numbers too much, the point is the design direction he'd be pushed in, not the exact numerical state.
Thanks again to any and all who took the time to read the whole thing. If I could give a TLDR that wasn't like a paragraph long anyway, I would, but I don't think that's realistic.

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--> literally Blind.
just to name three jungle champions. One caveat: someone like
will still beat teemo if he gets on top of the little sucker because although teemo can blind udyr, the effects of his bear and phoenix stance aren't tied to actually assigning damage from the autoattack but rather completing the animation (idk about tiger)
as an item, at least the way I play him.
and