9. The Cybermen
I hate to say it, but it seems to me that the Cybermen are the wannabe Daleks. I'm not a very big fan of the Cybermen myself as they don't frighten me as much as I think they should. They just don't feel like such a threat any more. Now correct me if I'm wrong, but the Cybermen have never seemed to raise questions that we need answers to. So who cares if they have a little break? And so when they do return, their comeback will have a bigger impact. So for me, the reason why the Cybermen need to retire is due to overuse. And ever since the Cybershades from "The Next Doctor", the Cybermen have never been the same for me.