How to balance Eve

Her main issue, which has been an issue for a lot of champs, is her stealth. Trying to balance a champion with stealth is a nightmare, especially an assassin (which are kinda hard to balance anyway)

Therefore, remove the stealth, and add a new passive that allows her to only be seen by true vision on the map. Therefore, you can always see her on your screen, so you can react when she ganks, but she can never been seen by regular wards or minions, only by towers and pinks.

Then she can be adequately buffed so she can be competent without blowing people up before they even know they are fighting while maintaining a type of stealthy gameplay.