I think a bonafide enforcer would be great, but agree with others about cost. We can't afford, and I personally don't think it's worth it, to buy a Josh McGuire or a prop who will command a massive salary.
For mind it's a Steve Matai type who plays in the forwards, someone who the opposition just think 'god I don't want to run into him'. A prop who really says 'follow me boys!'. Mark Carroll is a good prototype for me. Someone a bit crazy and just throws his body at the defensive line.
Who is that in the comp currently? Tough one, I do think the coaching staff need to get into the ear of the current players and let them know that there is a vacancy currently. And if someone wants to put their hand up they will effectively be captaining the forwards.
This year there's been players like Gavet from the Tigers who I think would be ok, seems keen to show the league he's a hard man.