I get that Riot wants to not have his revive always available. Fine. However, his current Blood Rush is not the easiest thing to keep active or sometimes even acquire depending on the situation.
One thing that would help is improving his ability to chase down enemies. Keep it windowed in Blood Rush and allow it to be something that benefits him based on how much missing health the last champion that Aatrox hit has.
So for example "During Blood Rush Aatrox is Ghosted (he looks cool hovering) and gains 1% movement speeds for every 5% of the targets missing health"
This would make reward him for getting an enemy down to low health, and allow him to chase, which in turn helps him of course get kills but also makes it easier to keep his Blood Rush active. If you run the numbers I think you would see the bonus movement speed is going to range from 5%-25%, but more typically 10%-20% if chasing a squishy carry missing half health thru nearly all of it.
Too strong? Still not enough for Aatrox?