Aatrox is very good at the moment, I can see that, and riot is getting rid of hit revive part of his ult. Now let's be clear here, the revive ONLY happens if aatrox kills a champion first, which therefore means that you can stun him when he tries to tower dive, so you can kill him before he can kill you, and take the last turret shot so he can revive. His revive part is already that simple enough, but getting rid of that makes some complications. First off, his base kit is pretty strong, but the reason why he can do so much damage is the sweetspots of his q, which people need to dodge to avoid taking massive damage from the second or third cast. This ability is enhanced by his ult, because not only the damage increases but the healing, which is why aatrox in his ult form is a little overextended in terms of how strong can we make this ult. The healing is what makes him mainly survive, not his revive, his revive can be easily counteracted if opponents know how to secure him once he revives, sort of like how someone waits to finish off someone after they used stopwatch. The healing however allows him to stay alive much longer than he should when rushing in.
Also, another thing that really sets me off that riot is getting rid of the revive is that it gives away the core attribute of the champion, being able to revive based on their brutality, which even old aatrox was surrounded of with his kit. If they took away the revive, it wouldn't make aatrox... aatrox. He would just be another riven clone because let's look here... triple cast q with knockups, a short dash, cc, and an ultimate that enhances their attack power. Aatrox wouldn't feel any more different anymore than other existing champs like riven. The self revive for getting a kill is what made him unique, it makes players have the "I can take em or I die" sort of feeling.
But there are some pros to getting rid of his revive in terms of it. It makes him easier to deal with for other champions, and can prevent the GA and his ult stacking sort of shenanigan. Those are really the only pros I can technically find.
Once this revive is gone, aatrox is literally gone, it's not even the champion it was intended to be anymore.