If fizz does get touched on in an update please do properly this time.
Just a simple request (long one btw) to the design team: Don't touch fizz until a rework is ready.
We've suspected some adjustments to AP assassins for awhile, you've reverted leblanc changes that Fizz shares, you even confirmed akali is on the current rework schedule, so there's alot of evidence that suggests he may be finally getting some attention. If he doesn't then that's pretty bias, but whatever I guess.
My main point is that if you are looking to give him attention then please just put in the additional effort to create a better rework for the champion, even take more time if needed to get a better design. The assassin update ended up just putting him in a worse state functionality wise than he was before and that left him a position where you could say "We already gave him some attention and thus we have no obligation to go back and invest in a full scale rework of the champion".
This was the TLDR so beyond this point is me suggesting focus points on what would need to be looked at if a rework were to occur.
Main issues with Fizz design is probably how linear the champion is. Unlike the other assassins in the game who have free reign to use their kits however they want Fizz has always been locked into a single type of fight pattern. There's little to no variation, it's predictable, easy to counter depending on your abilities, and the best way to describe it is that he's basically a walking flow chart. He's forced into this position where it's a pseudo stat check. If you're of a reasonably usable skill level and have the champion kit for it, fizz will be of no real threat, on the other hand though if you lack any real means to counter him then you're mostly screwed.
I'm not only talking about rework fizz either, this is how he's always been. The reason why Fizz could be considered "better" before the rework is that as a game league was nothing like it is today. The champion pools consisted of little to no major mechanical counters for fizz, Damage was lower so Fizz had more room to fight instead of dying in less than 2 seconds, and most importantly itemization was entirely different, almost completely lacking the colossal amount of defensive stats, actives, and passives that exist today.
In terms of rework mechanics I'd focus on 3 major aspects:
Remove damage delays from his kit. The only other assassin who you could compare this mechanic to is Ekko, and even his "delay" on his passive is significantly easier to manage than having to wait a staggering 2 seconds. There's also the fact that his kit was built to be much safer than Fizz in that aspect, so at this point there's no reason in handicapping the champion with this.
Change how his mobility mechanics work. He has a short range targeted dash that for no good reason is dodgable. No other champion in the game is handicapped with this sort of mechanic. Jax, Irelia, Lee Sin, just to name some major ones. When Fizz misses his he's also forced to use his E just to catch up to the person, otherwise he'll never apply his W mark to have any sort of chance at dealing damage. When he does this that mean he's out of options, no mobility, no safety, nothing, just an assassin with no resistances standing there for 2 seconds waiting for a W proc that 90% of the time won't kill because he's sacrificed every other damaging spell just to get in Auto Attack range.
His E is also a major problem. It serves as his Primary damage, Primary mobility, Only wave clear, and the only means of safety in his entire kit. In almost all situations he needs to sacrifice one of these just make use of the others, commonly he has to sacrifice 2. Like his ultimate (which is my next point) there's too much reliance loaded onto a single ability, and to make matters worst it's also often times easily counterable. Not exactly what I'm talking about but there's the bug that has existed for years where a blitzcrank can knock fizz out of his untargetability which has never once been addressed, similarly a recent oddity has popped up where it appears fizz isn't staying untargetable for the full duration and is leaving that state early which puts him in danger for the remainder of his troll poll animation.
I could sit here all day and pitch rework concepts presenting ideas on how to fix things but since I've already done that I'll just give a brief request. His Q should be a free aim dash, nothing else really needed. His E should have the damage removed entirely and have his primary damage components split between his Passive, W, and ult. I'd personally like to see it turned into the same style as Yasuo and irelia, a rapid fire mini dash for quick mobility in a limited area. I'd make it free aim instead of targeted on minions and simply reduce the untargetable duration to half a second or less, however long the dash itself lasts. It'd create a much more skill based playstyle involving properly reacting to abilities and dodging them which his current E does but in a much clunkier way, though that concept is up for debate.
Finally, the last point is his ultimate. It's simply the exact same thing as his E. His ultimate has too much of his kit relying on it, so much to the point where if you do not land your ultimate in an optimal way or an intended target then Fizz is boned. He's not like other assassins, he'll blow everything just getting to the target to proc the W mark and almost always die, best case scenario is that he trades kills for the target. Issue with the best case scenario though is that it usually means some REALLY squishy target with no resistances, and if you do manage to pull something like that off then you can expect a wave of rage coming at you for killing someone with W alone.
Ultimates on any champion are very important to their kit, but atleast in terms of assassins I can't really think of any others where if they don't have them then they can't do anything period. Though who knows, maybe fizz is the balanced champion and the other assassins are broken?
Originally I would've complained about assassin itemization not being available but I've come to not care anymore if we can stack more flat pen than the average champion has in resistances at level 18 base stats, not even counting the % pen (More lethality items when?). Rather I think I'd be happier with Fizz being better adjusted to standard AP items.
Major issue with that in the past though has always been power spike problems. Fizz has one of the worst, if not arguably THE worst general laning phases period. Forced to face tank countless auto's and abilities trying to CS, often times losing 1/4 of your HP at level 2 just trying to get a single melee minion, and don't get me started on the pain of ranged creeps. Before, this problem was rectified by something simple, if you can't farm the creeps then you can just farm your lane opponent. But fun times don't last forever and now with early game poke up, Nullifying orb existing, and stop watch being a virtual middle finger to your level 6 cheese (if there was room for one at all), successfully dueling and killing your opponent for a snowball lead is something that is long gone depending on your matchups.
So almost every single game you play you're forced to sit at a disgustingly low CS count and thus you get starved on gold. Buying normal AP itemization is out of the question at this point.
Depending on how the rework turned out, (if you're even going to listen to me pleas for help at all) the idea of turning around this utterly garbage laning phase is out of the question so instead I'd think more finely building him for massive scaling would be far better.
How you'd go about this is something I can't objectively give an answer on, but it could be something classic like Mana scalings similar to Ryze or Kassadin which could open up more options for mechanics in his kit, or it could even be something like tweaking the scalings to higher levels than they are now. Could even implement a mechanic where his ratios increase as his AP goes up, the options for creativity are endless in a game like this.
For the moment I'll continue playing casually because it's hard to enjoy the game when Fizz is so frustrating to play, but if he does receive a rework then I'll happily climb back to diamond and start enjoying league again. Normally I wouldn't have bothered to make these posts any more but as I stated above there was the AP item changes, Leblanc having her passive that she shares with Fizz changed, and the fact that Akali is on the rework schedule when she's largely in a similar position to fizz. If there was ever a point where Fizz is going to get consideration for an update then it'd be now, and if I can magically get the design team or anyone who'd be related to such matters to read this post and consider what I'm saying then I could possibly influence a better rework if it were to happen.
So it was worth a shot. The rest of you chaps have a nice day and remember something: If you find fizz frustrating to play against just remember we're probably just as pissed off while playing this champion on a regular basis.