If I were to rework Aatrox I would make him feel like a godly warrior in battle

Passive is whenever an enemy unit near Aatrox dies to him heabsorbs the blood into his sword and increases his swords size and shape based on how much blood he absorbed. Any excess blood he absorbs(meaning after he is full and another unit near him dies) he absorbs it as health. Blood in his sword interacts with his abilities.

Q would be the same but longer cooldown, a slow on it unless knocked up, and a bit more range. Also can't be affected by CC while in mid air that would reposition him(knockbacks and pulls). Other CC takes effect once he lands.

W is where he gets revamped tremendously. It is no longer a toggle but instead an active sort of like Irelia W but a little different. When active his sword becomes empowered and draining the blood with every auto attack he deals until he is out of blood. If he hasn't auto attacked for 1.5 seconds he loses blood rapidly. His empowered W lasts for 6 seconds, when he runs out of blood, or dies. His auto attacks drain a small amount of blood and deal a small amount of damage that racks up and stacks up to a highish number. He gains bonus attack speed with every consecutive auto. If he doesn't auto attack for 1.5 seconds all the stacks drop off. It can go up to a crazy number like 1/5 of his blood is drained with his autos when fully stacked but deal a tremendous amount of damage.

W passive is he gains some blood when auto attacking large monsters or champions equal to 2% of the damage he does with his autos outside of the bonus damage from his W.

E is sort of like live but with a twist. His E if just tapped goes a short range, deals low damage, lightly slows, and costs health instead of blood if he has no blood. If Aatrox has blood in his sword he can charge the ability sort of like Varus and draining blood while charging. If he drains his max amount of 40% of his total blood it will turn into a projectile similar to Ezreal R(not global though), will go nearly 3x as far as just lightly tapping his E, and will deal 2.5 damage of tapping E but no longer slow.

This ability is meant to be maxed vs hard match ups/ranged champs. It won't be superior to his W if he is able to actually get in melee range and stick with his enemy.

His R is the next big revamp and really ties in the whole godly warrior play style. Similar to live he deals damage on activation, gets some blood for each damage champ, and is bigger while gaining auto attack range. But the new thing is he no longer gains attack speed but instead a leech on his sword that heals him when he auto attacks enemy champions for a nice amount. His W when activated stays active until his R runs out. His R lasts 10 seconds if he stays in combat but immediately runs out if he hasn't attacked an enemy in 3 seconds. Any kill he gains while his R is active on champions fully refreshes his R duration.

If Aatrox is allowed to constantly stay in the fight and keep attacking his enemies he will literally dominate the entire teamfight as he racks up and destroys you. His big weaknesses are as following:

Kiting, so almost any adc will be able to shut Aatrox down.

CC of any form that keeps Aatrox away from enemies. Warwick, Ashe, Malzahar are a few that would ruin his day.

Jax and Shen as dodge will not refresh or keep his W and R going.

Attack speed slows will kill his dps by a lot.

Burst is also something that will counter him(as about 100% of the roster).

But his biggest weakness is how he needs to ramp up or he will be useless, sort of like Darius(needs 5 stacks or he won't do much).

His strengths are as following:

Vs tanky comps he will have a field day in never losing fights unless he is cc'd to oblivion.

Low mobility comps as he will have limited mobility and CC and those that cant run from Aatrox are going to have a bad time alone.

Baron and Dragon clears as he will eviscerate them once stacked and if a team fight happens right after he will already be ranped up(sometimes).

Being in a "protect the carry" comp built around him. If his team was Aatrox Top, Orianna Mid, Maokai Jungle, Ashe ADC, and Lulu Support Aatrox would be able to run the enemy down while his team keeps him alive forever.