If you're using it to execute, you're being a massive dickwad and should be shot on sight. The fact that you could come into the fight late, ult, and then royally fuck up the team is just bullshit. It makes more sense that a % damage spell is limited in some way. The way they do that is by making stuff either stationary dot % damage (null zone), absurdely low aoe % damage (despair), single target (bio-arcane barrage), scaling off current health (crescent sweep), or scaling off missing health single target (fizz).
Eve had a burst damage, aoe, cc inducing, low cd, shield giving, % health damage ult. Literally no other champion has a comparable ult at this point, except for xin, but his doesn't scale with his stats, and it's % current damage.
Combined with a kill/assist reseting as/ms boost/minicleanse, a low cd aoe mid damage nuke, and a high damage, low-mid cd single target nuke, with passive invisibility, and you have a recipe for opnerfpls.
And this is excluding the ear-rape that ult makes whenever it hits.
Eve needed the nerf. I have yet to hear an argument against this other than, "but now i can't press r to win"