The reason why Jax is better than Aatrox

Its really simple.

Jax's hard CC and his engage/escape are not all in the same long cool down ability. If you use your CC and things go south, you can still dive to a minion or ward. Or if your dive is on CD you may still be able to stun them (after mitigating damage, which Aatrox can not do)

Aatrox's everything is tied up in his Q, and unlike jax dive, it can be interrupted so its not even reliable.

Furthermore, Jax does mixed damage with free magic damage every 3rd hit passively from his ult.

Pretty simple stuff gentlemen. It really makes you wonder about the level of competency of the designers.

Stop putting Riot on a pedestal. They make some very poor decisions quite often.