My problem is that he has he speed increase at all. Without that, I'd probably be completely fine with Blitz. Not that I have a huge problem with him or anything, he is as he is and has been for years, I have no qualm with it.
If you look at DotA2 (yay, I get to bring up that game again!) you see Pudge, a champion with a similar pull, but rarely complained about - except maybe on a couple forum QQ posts because they didn't ward properly. And I think there are two reasons: 1) Pudge has no built-in gap-closer of any kind. None. At all. He has a pull, why does he need more gap-closing power? Especially since it closes the gap for his team as well 2) Pudge's combo takes longer to do anything with while Blitz does his instantly.
Now, I'm not saying Blitz does or does not need reworked, but a comparison from his inspiration hero (you cannot tell me he was not inspired by Pudge without lying -- and that's perfectly okay) is kinda interesting. It speaks a good deal about how the games are balanced differently.