Midna is certainly a mysterious character, it'll be interesting working with her on your new quest and finding out what her true motives are.

at the moment i like the idea that she's been imprisoned as someone (Ganon?) has taken over her realm and she wants it back. The slogan being 'You gotta fight Evil with Evil' like it said in the Hellboy and Riddick film trailers

One thing puzzles me though, if that other eye part wasn't broken off her crown/mask thingy how would she be able to see!??