They both provide instant gap closers, I'd relate it more to Amumu in this case, but since the target can also be pulled, Blitzcrank and Naut are also applicable comparisons. He provides a large mix of utility in one spell which can really shut down an enemy.
Again, they're not the same. Yes, the Q double activate is similar to Amumu but the Q single activate is NOTHING like Blitzcrank. It's more of a slow/snare then it is a pull. I'm not saying that I think it should be changed, I think it's fine how it is. I'm just saying that a lot of people have been comparing it to blitzcrank and it's not. Amumu's Q is also a stun whereas I think if you use Thresh's "jump" portion straight away there's no snare/stun.