When I am looking at puzzle caches it is unclear how much of the difficulty rating is due to the puzzle and how much is due to the way in which the cache is physically hidden.
For example, take a puzzle cache where the puzzle is extremely hard, but the cahce itself would be a 1 star difficulty without the puzzle. Conversely, take an extrememly well hidden cammoed micro cache that has a very simple puzzle attached to it. Or what about a cache that has a very difficult puzzle and is also well hidden.
To separate these two levels of difficulty, I suggest creating a third rating called "Puzzle". This could either only show up for puzzle caches, or it could be set to 1 for all non-puzzle caches.