The Problem with Ashe
Ashe needs a rework; she has too many fundamentally overpowered pieces in her kit that make her impossible to balance. At the same time, she is one of the more iconic champions in League of Legends, so any rework would have to take extreme care in removing as little of her identity as possible.
Every champion in League has a gameplay identity and a lore-based identity. For Ashe, her gameplay is supportive, she has the feel of a leader with her ultimate and other utility. This ties in with her lore identity. Ashe is a strong and decisive leader; she prefers diplomacy, but will not hesitate to fight if that is her only option. Ashe's current kit is a good reflection of herself in the lore, but it is not at all healthy for the game. Below is a few changes that keep her identity mostly intact, but allows for more counterplay both for the enemy team and for Ashe and her team.
Base Stats: Movespeed up to 330 from 325
Ashe had way too much crowd control to give her any sort of mobility whatsoever. This update gives a lot more counterplay opportunity to her opponents, so it seems fair to finally give her just a bit more mobility.
Focus (Passive): Ashe now gains critical strike chance while out of combat instead of focus stacks. She loses a flat amount of her bonus crit for every crit she lands after attacking.
The first sentence basically reverts her passive back to the one she had before 3.8. But now, instead of being punished for attacking by losing all her stacks, she is rewarded for being patient. People have been complaining about the uselessness of Ashe's passive for a long time, but most of the ideas centered on her gaining damage through being in combat rather than out. That is rather contradictory to Ashe's lore, where she prefers to reserve fighting as a last resort. This change still rewards her for being "diplomatic" and not fighting, but it no longer punishes her when she has to fight.
Frost Shot (Q/A): Is now an active instead of a toggle. Ashe's next basic attack deals bonus magic damage and greatly slows. The slow diminishes over time.
No more perma-slow. This ability was pretty much the entire reason Ashe had to be left in an unviable state. Perma-slows are not fun; they do not allow for any sort of playmaking on either side, and only feel moderately rewarding for the player. The new ability allows Ashe to make reactive plays and gives her opponents windows of opportunities to take advantage of.
Volley (W/Z): Slow now scales with rank in itself instead of rank in Frost Shot. Enemies can now be hit with multiple arrows. The slow from each arrow stacks, and damage from each arrow beyond the first is reduced.
Having two abilities that scale with the rank of a single one is poor design for multiple reasons. There is a lack of clarity; it doe not feel as good to max a certain ability, etc. Now that Volley fully scales with itself, it can feel much better to max out no matter when the player feels like it. Changing Volley to be able to hit targets with multiple arrows also provides clarity. Ashe can no longer weave a single arrow through minions when her opponent thought she was well positioned. In the lategame, it gives her an incredibly strong slow at point-blank, while still allowing counterplay through skillful positioning.
Hawkshot (E): No longer grants passive gold; now grants movespeed in the revealed area.
Free gold means that the player gains an advantage by being just as good as his or her opponent. That hardly seems fair. Removing it allowed the addition of a little bit more mobility into Ashe's kit, while improving the lore-accuracy of her kit.
Enchanted Crystal Arrow (R): Maximum stun duration reduced; minimum stun duration increased; travel distance until maximum stun decreased. Slow duration changed to twice the stun duration, from 3 seconds. Slow percentage now scales with rank.
It is not any fun to get hit with a max range Ashe arrow and be stunned for 3.5 seconds, nor is it even all that rewarding for Ashe to land a max range arrow—she will not be able to participate in the rest of the fight anyways. These changes put less emphasis on landing long range arrows and more on landing multi-champion arrows. It was always a strong initiation tool, but now it is even moreso, while sacrificing a few of the frustrating edge cases like max-range and point-blank hits.
Overall, these changes seem to adhere to Ashe's identity just as well, if not better than they did before, while allowing Ashe's opponents, as well as her and her team, windows of playmaking opportunity, as well as much more opportunity for counterplay. Her numbers can now be adequately balanced without her kit making her overpowered, which means she'll feel even more rewarding to play, not only through her identity, but also through her role in a team.