I don't think it's a bad idea at all, just difficult to work. I seem to remember Pprune having the User Reputation enabled in the past (it may have been another board though) and it caused all sorts of hissy fits and tantrums!
I have seen a board that used a "thanks" system. If people found a post interesting or useful, then they could click on it and the poster recieved a "thanks" next to their name. It helped sort the wheat from the chaff so to speak.
Though I have no idea if this board sotware offers that sort of thing.
It might be an idea and could help cut down them amount of rubbish that is posted all across Pprune, not just in Private flying. Rumours and News is just a total bunfight now, full of posts by people with the aviation knowedge of a bag of peanuts.
"I fly as a passenger once a year, but here's what I think caused this accident..........." Give me strength!