IMHO, he's probably going to get changes in the now presumed "Diver" update now that the "Tank" update is under our belts, or a VGU, if his performance starts to really suffer, depending on what happens in the future.
The reason I would think with the "Diver" possibility is because of his Q and E, because it acts like a dash, like many of the other "Divers" or "Skirmishers" have with their mobile-abilities.
I can also see why you'd classify him in the Darius/Juggernaut category, though our reasons MIGHT not be the same. I myself would think it's because of his ult.
While you can trap more than one person in it, it gives more of the feel (to me at least)...
"It's just you and me. Mano-a-Mano."
...when he uses it. When looking at THAT, I can see the want to classify him in the Juggernaut-role, because that's a sort of one-on-one thing that most Juggernauts excel at.
But that classification runs into a problem with his Q and E, which gives him MORE mobility than a Juggernaut is expected to have. That's just MY two bits on the subject.