@Meddler, Input about Aatrox lacking "War" and too more "Bore"
Aatrox's fantasy theme to me screams "War lusting devil with big sword", but much more plays like "AFK split pusher until he's IS the 1 man army." ~ That's fine but we got Tryndamere for that title already. Aatrox should not play as a one man recking crew but more like: The bloodier the battlefield of war around him gets, the stronger Aatrox should get too. His kit could boast greater possibilities thus he might be falling short on and should be taking more ideas from other champions like... Trundle.
Trundle's passive is often overlooked as simple mechanic but it's perfect conception of this war lust theme, Aatrox should take notes on being more similar to, simple put: King's tribute: more death around Trundle (the bloodier the battle) = more reward in the form of healing to him. (That sounds more War like than blood pools current state). Also Aatrox as of now is surprisingly too dependent on farming items. I get part of his kit is built around the double edge sword theme of choosing damage or healing, but his kit could reward him in healthier ways than farming a life steal item to cover his spell costs. Think like a Troll- borrow great ideas from great champions like Trundle to get health back.
Aatrox should gain temporary spellvamp stacks (or something) off the bloodier or the number of champions involved in the battle. - a passive that rewards him potential health being close to large brawls, something he's not rewarded on right now with out investing in a Hyrda first.
Hope this helps