So much potential wasted - look at Percy, for another example - what was the POINT of "Prefects who gained power" (and you are trying to tell me that Riddle wasn't in there? and Percy going over to the Ministry if he was going to be completely wasted and just turn up and say "Oh Hai, I'm sorry."

Yeah, I don't get this subplot either. What was the point of ostracizing Percy from his family? If JKR didn't want to write more of him, simply have him move to London and be done with it. I suspect this ties in with the whole "Arthur was supposed to die in OotP". But since she chickened out and didn't kill him after all, this went nowhere and she simply decided to keep Percy's story as it was.