I think the dungeons weren't as hard as they could have been. The design of the dungeons were relatively basic, almost guiding you through. I felt like they were somewhat hand-holdy. The dungeons were rather linear, and along with Fi's information, you were practically pointed towards the right direction. Sky Keep wasn't like this as much, since there was no permanent structure to the dungeon. There wasn't really much of a way to get lost in any dungeon throughout the game.
The puzzles were challenging without the right equitment. Take after you get the bomb bag, for example. With the map, you see what needs to be done in order to continue. Without it, one could pass by the secret (I won't say what it is, just in case someone hasn't gotten to this part of the game yet) and never look twice. It was enough to make you think for a few minutes, possibly refer to your items, then move on.
The bosses were easy, but they were good bosses too. Most had an obvious weak point (giant eye, heart in it's chest, etc.), indicating a way to defeat them. However, most forced you to utilize the item you found in that dungeon in some interesting ways. The normal enemies had to be defeated by swinging your sword in a certain way, showing off the amazing 1:1 motion controls.
The dungeons could have been better, especially in their layout. The puzzles were decent, and fighting bosses and enemies put your weapons to good use and demonstrated the power of the Wii Motion Plus motion controls.
