you have to.
when a champion is fed and has no counterplay it's not healthy for the game.
and aatrox is one of these champs.
he is too weak right now, but flat damage buffs are definitly not a solution.
they should maybe work around his cd's a bit.
for example, his q is on a 12 sec cd even on lvl5.
they should maybe make it so that this gets reduced by 1 sec every time he attacks an enemy champion.
this way he'll get rewarded for being able to attack often,_ the thing he should do_, with a lower cd on his q that can be used to escape/land another knockup.
flat damage changes will make him either broken of unplayable, he'll need buffs like this that reward him for doing the things he should do without making him broken.