Kai'Sa's Kit is Extremely Overloaded
Exactly what it says on the tin.
Seriously, the evolution idea is not at all a terrible one, seeing as Viktor and Kha'Zix are the best examples (and only ones that I can think of) that have this mechanic, but do it much differently compared to Kai'Sa. For those who don't know, Kha'Zix evolves his abilities at levels 6/11/16 with each point he puts into his ult, whereas Viktor evolves his abilities by purchasing upgrades to an item he starts with. However, Kai'Sa has to build a ton of different items to evolve hers (100 bonus AD for her Q, 100 AP for her W, and 100% attack speed for her E). When she evolves any of these abilities, they become way more op than they should. As cool of an idea as this is, it definitely is not executed well for Kai'Sa at all. She has way too much going on in her kit to properly balance her. So here's my suggestion:
Remove the evolutions, and balance her out around that.
Icathian Rain - Q: Evolution REMOVED - Instead of 6 bullets, or 10 when evolved, Kai'Sa fires 8 bullets that deal 60/70.25/80.5/90.75/101 (+40% bonus AD) (+45% AP) damage. Reduced damage deals 15/20/25/30/35 (+10% bonus AD) (+12.5% AP). Maximum single-target damage = 165/210.25/250.5/300.75/346 (+110% bonus AD) (+132.5% AP).
With this balance change, she'll still be able to farm effectively, but also won't be able to 1-2 shot someone once she evolves the ability at rank 3 or 4 of the skill.
Void Seeker - W: Evolution REMOVED - Void Seeker will only apply 2 stacks of Plasma, but will deal 10% bonus damage to champions if it pops the Plasma debuff. The blast will deal 35/55/75/95/115 (+150% AD) (+65% AP) damage.
Kai'Sa may not be able to stack her Plasma that fast before a fight or as an engage tool, but the player will be rewarded for trying to finish off a kill with Void Seeker.
Supercharge - E: Evolution REMOVED and Invisibility REMOVED but moved to Killer Instinct - Kai'Sa now charges for 0.8s gaining bonus movement speed scaling from 25% - 75% based on bonus attack speed. After charging, Kai'Sa gains bonus attack speed for 4 seconds. Minimum movement speed increase: 40/45/50/55/60%. Bonus Attack Speed: 50/55/60/65/70%.
There is a good reason why the invisibility makes more sense on the Ultimate rather than a basic ability, and I'll touch on that when I explain the changes for Killer Instinct. With this change, she won't have to completely rely on her bonus attack speed for a movement speed increase, and will already start out with a good portion. Giving the ability more attack speed will also compensate for the lack of invisibility.
Killer Instinct - R: Invisibility ADDED - When Kai'Sa completes the dash to her target, she will gain the shield, but also 0.75s of invisibility so she can better position herself. Scaling for the shield will be adjusted to balance out the addition of invisibility. Shield Strength: 100/130/160 (+80/125/170% AD) (80% AP).
As stated, this change will allow Kai'Sa to better position herself after successfully dashing to a target, rather than wasting her invisibility to charge into range so she can dash to the target.
Let me know what you think. This is just my honest opinion of how her kit would be more balanced. Everything else including mana costs, cooldowns and attack radius/range of each ability will stay the same.
