The Ravenclaw common room is the only one with a hint. This isn't very fair. I realize the riddle is part of the roleplaying experience, but it's not fair that once someone gets it right (Or looks it up online) they have endless access. This is true of the other houses, but their passwords can't be found online, and aren't easilly guessed. Plus, the passwords change in the books and movies. If we need to be fair, they could all change, but Ravenclaw certainly can't stay the same forever.
Right now, there is a petiton going around getting everyone's votes.