Ashe rework
This is a long one (sorry!), but I think it could be a really solid rework, so if you'll bear with me...
Ashe hasn't really had the best time adapting to the current meta. Due to the fact that she doesn't have the mobility or damage needed for the current meta of hyper carries (until super late game), she's become sort of a niche champion. She has an extremely passive kit, which doesn't fit with the current direction that Riot seems to be going for, or with how an adc/marksman should be played. She doesn't have any natural damage output modifiers, which are almost necessary for the current meta - Kog'maw's Bio-arcane Barrage, Tristana's rapid fire, Lucian's lightslinger, etc. She also only has one ability that has an AD modifier. If she's going to be a viable champion, she needs to have a more versatile, active, and cohesive kit.
First we have her Frost Shot. Now the problem with this is the same that used to exist for Kayle and for Sivir. Having an ability that just adds a bonus effect to auto attacks while triggered for a low mana cost per attack just doesn't work. It makes for a very cheap and passive play style. Instead of asking yourself "is now a good time to use this ability", Ashe players essentially say "Do I have over half mana? I do! I could be using frost shot". It does let her stick to enemy champions, but there's really only one scenario where Frost Shot comes in very handy - when she's chasing down a single target by herself for an extended period of time. The problem is that this is not a common scenario for an adc to be in. Adc's rely on cc and kiting from support and other allies in order to be able to get their own damage out. That doesn't mean cc on an adc is useless, but if an adc is in a one on one situation, that champion should be able to rely on some stronger cc to keep the enemy champion at a distance or lock them down because that champion is probably better suited for one on one. It makes Ashe more of a nuisance than a threat until it is maxed out.
The second problem is the passive gold generation on her Hawkshot ability. It doesn't make much sense to have a gold generation ability on the champion that is already designed to have gold channeled into them from kills and farm. That's why gold income items were made for supports, so that they could have a little bit of the love without taking it from the adc. I would much rather have an ability effect that increases damage output directly, instead of getting me gold a bit faster so I can get items to increase my damage output.
Lastly, I want to go back to her passive. Her passive falls under the category of "If I don't attack for a while, my next attack will do more". While this works for a champion like Thresh, who can wait and use it to poke enemy champions, it doesn't make sense for a champion that is designed to constantly be farming or attacking. Because of this, her passive effectively becomes little more than an automatic critical strike after she returns from base.
Now that's a lot of things that I think don't work with the champion in the current meta. Here are some of the changes to her kit that I think would fix these problems.
Focus (Passive): After killing an enemy minion, champion or turret, Ashe's next basic attack is guaranteed to critically strike.
[I think this is an acceptable change to her passive that makes it relevant both during the laning phase and during team fights and keeps the strong critical strike focus of Ashe.]
Frost Shot: COST - 30/35/40/45/50 mana, COOLDOWN - 20/19/18/17/16 seconds Active: Ashe's next basic attack deals 10/15/20/25/30 (+0.1 AD)(+0.3 AP) bonus magic damage and slows the target for 10/15/20/25/30% for two seconds. Frost Shot can be activated three times before it goes on cooldown. The consecutive slows on the same target do not stack, however if all three Frost Shot attacks are landed on the same target, that target is stunned for 1 second.
[This change would do a few things. First, the damage buff to her auto attacks would give her a natural damage buff, which is something that Ashe sorely needs to stay relevant in the changing meta. Second, it makes the ability a bit more active and requires the player to make a decision on when the best time to use the ability is, while keeping with the tone of Ashe as a carry that can stick to her targets and chase them down. Lastly, it makes the ability a little bit more relevant early game, where the damage buff, slow, and stun affects mesh well together even early on. Bonus: this makes Trinity Force, an otherwise almost ideal item for Ashe a bit more attractive] (I also toned back the slow to keep it from being too powerful)
Volley: (Volley no longer applies Frost Shot to enemies hit by it)
[Since Frost Shot is getting damage and stun affect, it seems a bit excessive for Volley to apply that now. Plus, with these changes, she'll need a nerf somewhere to balance it out.]
Hawkshot: RANGE - 2500 / 3250 / 4000 / 4750 / 5500, COOLDOWN - 60 / 55 / 50 / 45 / 40 Passive: While Hawkshot is not on cooldown, Ashe's critical strikes deal an additional 5/10/15/20/25% damage on hit. Active: Ashe animates a hawk to scout for her, granting sight for 2 seconds as it flies towards a target location. Hawkshot grants a 1000-radius area of sight for 5 seconds when it reaches its destination. The sight extends into brushes. (no change)
[Having the bonus damage to critical strikes fits well with her passive, and makes her kit a bit more cohesive. It makes her decide between using Hawkshot or saving it for the bonus damage if she is worried about an upcoming fight. As it is, Hawkshot is basically a "use it whenever it's up" kind of ability. This change would also get Ashe into the action a bit more by not forcing her to farm so much just so she can try to be a monster late game.]
Well those are my thoughts on how Ashe could be reworked into the current meta. I don't know quite enough to know how the numbers might be modified to keep this from making her OP (perhaps drop her base attack damage because of her frequent and powerful critical strikes), but I'm not looking to make the numbers perfect, I just think these changes would make her kit more balanced, cohesive, and practical.