Preface: this is just my initial impression of Aatrox's ult, so take it with a mountain of salt.
I'm liking Aatrox's rework a hell of a lot so far, but one thing that's stuck out like a sore thumb to me is the way his ult's revival mechanic has been handled: specifically, how his Blood Well builds up to his base HP over 10 seconds...out of a 12 second duration. To me, this creates a weird sort of situation where Aatrox is increasingly pressed to _die_ as his ult goes on, because if he survives the duration, he gets nothing; now, it's very likely that this was intended so as to not create a sort of "hopeless situation" for people fighting him. However, as it stands, Aatrox's ultimate just kind of...falls flat at the end, really.
If I could make a QoL suggestion for this, I feel like having a lesser version of the revival portion of Aatrox's ultimate happen if he **survives** the duration would help to alleviate this discrepancy, such as having his ultimate heal him for an amount depending upon how much of his HP he's missing at the end of its duration; maybe something in the ballpark of "equal to 10% of his base HP over 4 seconds" (if he's at >=75% of his max hp) and scaling up to 30% (if he's at <=25% max HP)? Mind you, the healing is still equal to his _base_ HP in this hypothetical, so it's still strictly a greatly reduced version of what he'd get if he died between the 10 and 12 second marks of his ultimate (specifically, 10-30% of the healing he'd have received had he died once his Blood Well was fully charged).