It looks like Aatrox is shaping up to be the same breed of fighter as Darius/Illaoi
So I've been thinking, and I'm starting to see Aatrox as a sort of Juggernaut/Diver hybrid.
Here's my thought process.
builds a hefty amount of defense while still keeping a solid backbone for damage. His job is to get into the thick of a fight, survive long enough to activate his passive AD steroid, and then change the tide of battle by dealing significant amounts of damage in spite of his tankiness. He has a % missing health heal on his Q to reward tankiness and give him adequate sustain to make it happen.
builds a hefty amount of defense while still keeping a solid backbone for damage. Her job is to get into the think of a fight, survive long enough to catch a good Test of Spirit and position her ult, then change the tide of battle dealing significant amounts of damage with a CDR/sustain steroid in spite of her tankiness. She has a % missing health heal on his Q to reward tankiness and give him adequate sustain to make it happen.
Now let's try looking at Aatrox the same way:
is now able to build a hefty amount of defense while still keeping a solid backbone for damage. With his 5% missing health heal and a more bruiser-oriented build, his job is to dive in and survive long enough to hit a power surge from his ult + passive AS steroids, then change the tide of battle with a greatly increased damage output in spite of having a more defensive build. The difference is that Aatrox is also a diver, which means he can jump right into the middle of a fight to initiate, but is reliant on auto-attacks for his damage output rather than being an AD caster like Darius or Illaoi.
Now, as someone who loves the hell out of the Darius and Illaoi juggernaut playstile, this vision of Aatrox is particularly appealing to me. A lot of people are having trouble with his passive, and Riot is planning on delivering some buffs (or perhaps ease-of-use changes?) in upcoming patches, but if Aatrox ultimately fulfills this Juggernaut/Diver hybrid class, I could be very keen on learning to play him. My worry is that his eventual rework with the Diver Class Update might take him back to being a damage-oriented diver (just in a healthier format), but until more news on that comes out, Aatrox has suddenly become a lot more interesting for someone like me to look into.

and abusing the free "attack speed" by having 0.4s cooldown on W (which equates to 2.5 attack speed) and having an extreme amount of damage coming from on-hit effects from BorK and Titanic. Aatrox would be able to tap into this on a non-URF scale, at least in theory.