I think you're assuming that words got down around 5 points because the players were giving A+ clues, but the word was far too difficult to be solved early. I don't think that was the case, most times. The words weren't "hard" -- the players just weren't solving them. Sometimes that happened because the clue givers were trying two disparate paths, making a "medium" difficulty word into a near-impossible one.
Anything that encourages the players to clue at less-than-100% efficiency is not good, IMO. One way to get at your idea would be to assign each word an overall point value based on its difficulty, and award those points no matter how many clues it takes. That way, the players are always trying to solve.
But all of the above doesn't make Password a better show, I wager.
-Jason