How I would change Aatrox to make him viable.
I have now played Aatrox even before his rework and mained him back in season 4, but one thing I do like is actualy his new kit and identity. One I do not like though is how akward he feels. Lifestealing was one of the things he is known for, so IMO if Trundle can have a pass with healing, Aatrox should be able to to.
What I would change: (I have two iderations.)
Passive: Increase his mutilated reduction by 10%
Q: I would reduce the dmg of his Q by 10%, not 10 flat, 10%, so 9/22.5/36/49.5 etc.
What I would add is a Quest.
Hit with the tip of your blade 20 times -> 50 base dmg on Q (This doesn't stack faster if multiple champions are hit at once, it needs to be 20 times, also might seem like alot, but hitting 20 Q's is not done in 5 minutes, especialy with the long cd in early game and how hard he gets countered by ranged champions.)
W: Nothing to change :)
E: Now heals on minions and monsters again, might be a bit less, but it was one of his key strengths, if you reduce his Q dmg, this might not be as oppresive, because, if Sylas can be alive, then he should be able to, to.
Now for what I would do, I would do a stacking system on his E equivalant to what has been done with Kassadin. This means, his E is on a very short cd, but it gets longer everytime you use it within a duration. (Right now it is very hard to hit triple Q because of the removal of his seconds stack, that is imo the biggest annoyance of his nerf.)
Fx:
Up to 4 stacks (Debuff should be on
2/3/10/20 (might seem weird, but this is because there needs to be a chance to hit his triple combo imo. also why in some way or form would nerf his dmg on Q, might also nerf his scaling by 5% on his Q or smth like that)
R: I like the PBE changes, but I would only keep the E reset (removal of stacks while ulted), and only reduce his Q cd by 50%. Everything else as it already is.
Might not be the right place for this, but hope atleast some rioter will se it :)