Honestly, I'd say that he's pretty overpowered in his current incarnation. It's true, he's not as good when he's not within his domain, but he really isn't going to have too many problems making sure that that is always the case. Once he hits level two in lane, his enemy is going to have a completely terrible time, because he's going to be able to pull them in absolutely at will. With Blitzcrank, you can at least hide behind minions, or dodge his grab. Naz is just inescapable, short of zoning yourself.
Plus, his ultimate makes him a ridiculous backdoorer. 30 second cooldown at max rank? You can get that down to an 18 second cooldown, and now you've got absolutely ludicrous mobility. Yes, there's a limit on where you can jump to, but with 5 potential locations, you can easily have one in each lane, one covering a major objective like Dragon, and another right in your base for easy access.