But hear me out...
What if you could flash away from targeted projectiles?
It's a mechanic that's been in League ever since the start (I'm pretty sure), but it's really annoying when you have the clutch play all performed in your mind, manage to make that play, and flash away to get out, just to see that autoattack (or that JinxQ) following you to your death,
It would be a new mechanic that players could take advantage of, for example:
Gosu doing Gosu things, going 5v1, kills one enemy and then sees a sudden Jhin 4th auto coming at him, so he flahes away to negate the damage.