[Wilfry]

All right so let me use my last surviving braincell while it's still breathing

How about we just implement the +rep and not include -rep instead making the person do a coherent and reasonable reply on why they aren't in agreement with those who make the thread.  This way if a -rep has to be given a admin could manipulate it instead of just having random spammers that don't like a specific person.  

Will this probably give more work to those who administer the forum? Yes, it could if they have to go thread by thread looking into any reply with "-rep" in it.

But is it a more controlled option?  In my opinion yes.  With only a small amount of people being able to lower your rep if needed it means that your rep won't be going up and down like a linear graph.

Is it a dumb idead? Well perhaps but that's just something that came to mind