Bad games with interesting mechanics

[Usyra]

However controversial this may be, I'll nominate the Golden Sun series. I like the idea of spells for combat having practical utility outside fighting, to solve puzzles and stuff. The problem with the game is that its mythology and characters are badly defined, in that the game can't decide who is or isn't an expert on the supernatural, how much of the supernatural is public knowledge, and in some cases lose track of these things over the course of a single conversation.