I don't think abolishing enmity-increasing skills completely is a good idea, but I agree that positioning should play a larger role in the whole enmity dynamics.

The skill "cover" for example would be fun if it actually worked like this: The tank stands between the covered player and the mob and gets hit when something would hit the covered player. Currently, when a Gladi uses Cover and the covered character is really behind him, he is still hit by front-attacks. So yeah, covering is a nice thing. I don't think any class should be able to cover, though, so it's not just position but also a certain competence to do it right.

There still have to be skills that allow the tank to "turn around" the mob when it's going for someone else. I imagine it would be very difficult to get between the mob and the archer when it is already running there. No chance really before the archer is getting hit.

So in short:
* Make positioning more important in general.
* Allow enmity to be generated from other places than right in front of the mob (i.e. provoke or damage).
* Only tank classes/jobs should be competent to cover other players. (Not sure if a skill should be necessary there.)