REWORK AHRI'S FOX-FIRE!!! PWWEEEZE!!! (<- not a sneeze)
Ahri is generally a balanced/ visually pleasing champion. However, right now Ahri's w is honestly in a very bad position. They're more like a part of her kit that is added in so that she can have a 4th ability, without causing balance problems, rather than an acceptable ability, both in terms of fantasy and gameplay.
First of all, her w is auto targeting, this offers very little counter play, other than moving away quickly before the last fox fire moves around. Riot compensates for this by limiting the dmg on her w. Now, personally, I feel that riot have always been trying to design abilities that reward skillful play on both sides (e.g. ekko's chronosphere giving an extended sec stun, getting past sol's stars makes him near-vulnerable), rather than making abilities weak because they require less skill.
This leads in to: secondly, her w is not very rewarding. If you land all 3 w it's like "oh ok, I did that", if you don't land all 3 w it's like "oh ok, I missed that." Even the cooldown is in a weird position. It's too short to be partnered with q, and e's cooldowns. While too long to be partnered with her ult/ quick follow up from initial wave of damage.
Thirdly, all the dmg, can be moved onto his q/ ult/ or e, because if ahri can get in range for her w, she usually does it through one of her other abilities. Not to mention, the targeting of her w is parallel with her ult, limiting the diversity of her abilities.
Ahri is like a super fun champion... but her w is just too awkward right now. Even if she doesn't need a full rework, update, can she at least ride along with some w changes this assassin update?
Well, I'm not just an all-complain-and-no-good-idea person. So I've a few suggestions to minor changes to her w. (These suggestions are flexible, you can take parts from one and parts from other)
Suggestion 1. Foxfire barrage (not the name, but just something so you can visualise) Make the fox-fires constantly surround ahri as a visual effect without dealing dmg. However she can expend them whenever she cast her w, like how gp used to expend his scurvy debuff whenever he use remove scurvy (which would then come back up when remove scurvy is off cd). So how exactly does she do that? Well, whenever she uses the ability, she skillshots them. That's right, she skillshots them, in a reverse cone towards her cursor (more like a ground targeted ability) (think heimerdinger's rockets), exploding in a tiny area when they meet at the end.
The idea, is that the explosion is meant to be the desired damage dealer, maybe even add a slow in, or a buff that doubles dmg/ charm duration or something. However this is where the "barrage" part comes from in the title - ability resets. Whenever she cast a spell, the ability resets, simple.
Suggestion 2. Movement incorporation Ahri is a very dynamic/ constantly changing her position champion. Instead of having her foxfire deal direct damage, have them represent a mark, each being 20-25% (depending on balance) of the mark. If all 3 hits the same champion/target they recieve 100% of the mark etc. The idea is that she deals dmg to the marked target within a timeframe based on her movement, kinda like how yasuo gathers his passive shield but as damage instead.
Suggestion 3. Hold back If ahri holds her w while she still have foxfires up, it prevents them from target selection, but continues to rotate. So she can have a bit more control. Simple.
Suggestion 4. The true corruption Kinda like varus's ult. But, if she somehow gets to mark her target with her w. Skillshot, or land all 3, or targeted ability, or ground targeted, or anything. The target will have foxfires cursing them instead, surrounding the target (like how they surround ahri, but not ahri) and deal damage to the target's own allies. Maybe even preventing shield effects or heals. After all, she is an assassin.
So that's about it. Please give it a thought, because ahri really needs a better w than just a spammable ult-without-dash.