My reason for thinking Plagueis is kind of overrated is that people place him above people like Caedus, Revan (among others) when there really isn't much proof. Yes Plagueis has some very impressive combat feats and Force power, but for the most part it's all speculative. He has no feats or displays of power that warrant the incredibly high placement he receives. That's not to say he isn't among the best, because we know based on accolades that he is, there just isn't enough on him to warrant placement above somebody like Caedus.