Just "F*** it" at this point. Try making him a physical damage support that buffs his team. Like Taric but more offensive oriented.
1) Allow him to charge his Bloodwell to heal allies or even revive them at the cost of his own life.
2) Ult is a Taric ult that's dynamic in its bonuses based on what you do.
3) Give him an ability that allows him to pick an an enemy in flight to put both him and and the enemy in suspension for a few seconds (WW ult but no damage).
4) Make his autoattacks on an enemy buff his allies autos on that same enemy.
5) Add an AD support item, similar to old Zeke's but less situational.
6) Give him an aura as a passive. 30% of Aatrox's bonus AD is given to all of his nearby allies (not to himself).
7( Keep his current E, but make it mark enemies that only allies can proc like Leona's Sunlight. This deals incredible damage and has a high AD ratio. Weak in solo lane, powerful in a duo.
Just my ideas.
It fits his character **so **much more and would give him a **unique** identify rather than being quite possibly the most boring champion in the game, bar possibly the champions that are getting remakes anyway (Taric).
Cue people going "But supports SUCK, why would you want champ to become one!?!?".
It's better than not really being anything and_ actually_ fits him.