If I understand the question correctly, you're asking about a class that does something like the smoker does, but for human players. For the most part, the engineer class is meant to serve that function. It's not pulling players away from zombies, but it can push zombies away from the player. Functionally it achieves the same goal.
I'm also concerned about the potential abuse of such ability. One player might use the ability to pull players away from zombies (which can be a bad thing in itself), but certainly some will use it to pull players into zombies (or perhaps off a ledge).
The real issue for me is finding a skilled programmer who can do this. The RPG code is complex. Making simple fixes/changes has been challenging.