Fixing Aatrox
This Patch (hotfix) Having to hotfix him this soon after release isn't a good sign. For those of you who haven't seen those:
HP up 30 Q damage up 5 E healing up 5% E dash range up 50 E resets your AA R CD 160/140/120 > 140/130/120
Not a bad set of buffs.
Cool. Here's where you should go from there.
Next Patch
In his stats, take away 15 base HP in favor of +4 HP per level.
On his Q, cause hits with the Edge to refund all CD's to some degree, not just his passive. In particular, make it refresh his E's CD between casts (not giving him a new charge instantly, but allowing him to instantly use it again if he had a charge ready).
On his E, increase the healing vs non champions from 33% to 50%.
On his R, cause his ult duration to refresh to a minimum of 4 seconds so long as he stays in combat with champions. In compensation, partially revert the CD buffs to 150/135/120. Grant his ult the 50 bonus range from Deathbringer Stance.
Long Term
Change his Q cast paradigm to mimic that of Camille's W, allowing him to move during its cast time.
Replace Umbral Dash with something else entirely.