I feel like Aatrox should have free spellvamp built into his kit.
It accentuates his high regenerative theme.
Allows Aatrox to still survive if he faces a heavy kite/poke team.
Promotes alternative build paths for Aatrox, such as AP (which E and R actually scales really well with).
Examples:
Massacre: Active: Aatrox unleash his full power granting him 20% spellvamp for the duration. (The spell vamp also procs upon the ability activation.)
__ (or) __
Blades of Torment: Passive: Aatrox passively gains bonus 2/3/4/5/6%+(1 per 60 AP) spell vamp for every attack and spell he lands for a duration of 2 seconds. This can stack up to three times.
__ (or) __
Dark Flight: Active: Aatrox spreads takes flight and slams down the target area dealing damage (like live) and granting 6% spell vamp for every champion hit for a duration of 2/3/4/5/6 seconds.
Just some examples above on how it could be put into his kit. I really think it would be a healthy buff on him, numbers are of course up for change if they are too strong, what do you guys think?
In general, this plus lifesteal is all the healing you'll ever need. In the event you absolutely, positively MUST have spellvamp, 
this will serve you well enough, and its stats aren't a complete waste on Aatrox.
