The design they were going for, and what they tried to accomplish for Aatrox, is honestly really smart. It's a great goal.
As Riot said, they wanted him to be a highly skilled melee duelist who works and outsmarts his enemies, utterly decimating them by being a more skilled fighter. Fiora shares a similar fantasy, but Riot has also expressed their failure in her regard two times; her skills are two 'catch all' and there's no real skill involved to hitting weak points.
#Aatrox' kit looks to succesfully accomplish this.
He's rewarded for dancing into his enemies with his Q, hitting them at just the right moment, and then dancing away from them / toying with them as they attempt to retreat and drawing them in once more.
This is also why he can't move during the cast animation; he's supposed to predict their movements / force them to go where he wants, and use his small E dash to make that happen. Being able to move at full speed would remove a lot of the 'skill' involved; just get them into the range, press button, transfer burden of skill onto his enemy.
His entire kit is designed to play around his Q and force enemies to be where you want them to be. His W is a slow and re-yank so that you can pull people into it when they think they've escaped, his E is to help reposition it when they think they're safe, and his ulti lets him get people into his ranged sweet-spot due to increased movement speed.
Is he currently too weak? Maybe, maybe not. The dude's been live for a grand total of about 24 hours, so given he looks to have an actual high-skill kit it's hard to say whether or not its tuned correctly. A couple of weeks worth of data and practice should tell us.
Regardless, his kit is much more interesting than it used to be, and his redesign was exclusively a boon.