Admittedly, I don't think that Nintendo necessarily intended to end Twilight Princess with a cliffhanger for Midna. I always viewed her saying "See you later" as a sort of cruel irony, considering that that was one of her relatively common phrases throughout the early portions of the game (specifically, she would say that every time that you completed a Tears of Light quest). That said, I think that there are ways that the Big N could bring her back without turning it into a contrived, fan-service-laden mess. ALIT's suggestion is just one of those. O' course, I would love for this to happen, and the only thing that gives me even a modicum of hope is that quote from Aonuma. Y'know...
"If we hear enough voices for her to come back, how can we not?"
Now, while I might just be delusional, I would like to think that Midna is one of the most (if not the most) popular characters in the series, outside of the main trio of Link, Zelda, and Ganon. Again, I think that her return could work if done properly, but I don't think that Nintendo -- when developing TP -- intended to use her again, nor do I think that they expected the character to garner such a huge following.