I love all three of the original trilogy films, but I would probably say that LC is indeed my least favorite of the three. Though, at worst, I'd rank it a 9.75/10, I just feel like they dropped off quite a bit with the crazy action. The story was solid as could be, but the action was a bit lacking. Could have been a lot more intense and packed. But whereas the action in the first two was cranked up to 11, the action in LC was right around 7.
No question the worst of them all is KOTCS. I've seen it probably 3-4 times total and I really have no interest in seeing it again. At least not any time soon.