I would love to see Midna back again. She was clearly the best of all the side characters in any zelda game, not only that but Link and her had a real connection, unlike with zelda.

Finding another way to the twilight world, (as the mirror was the only known one) would be quite cool

I don't believe she should come back.
because then they'd have to make the whole plot around twilight again...and zelda games are soooo much different from the next...i just don't think it would be a good idea for nintendo...

as it is hinted by Miyamoto link will have a new gaurdian in the form of his master sword's spirit or something similar. so from this information, I am sad and sorry to say that Midna is most likely not making a return in THIS new zelda game, but who knows, maybe a third one will come out later...

quote Solid Snake 4Life

Glue probablly can't hold together magical items. Besides why would Link wan't to see Midna again. All she did was use him. She didn't seem like a recurring character anyway her story did not seem adjustable.

Not to mention the pieces were that small it would be impossible to find them all and put them back together in the right way.

this would be cool ok here it gose gandorf uses his power and sends link through a portal and in the portal you see your partners from all of the zelda games like midna king of red lions ummm the two sidekicks at ww theres a deku and a bird the gorons,zoras,and dekus. navi and sheik and skeleton knight. aand you get to play as all of them i call it
legend of zelda portals

Personally, I loved Midna, but it would be wouldn't feel right to bring her back. That make a lot of Zelda fans furious, to have an entire game centered around Link trying to reach the Twilight Realm to see Midna again. The only way they could kinda bring her back is the thing they did at the beginning of TWW, where they had that legend thing. So basically it would be like this:
"However, a new evil assaulted the land of Hyrule, and yet the Hero of Time had vanished into a land of darkness, to live with the Princess of the Twilight."

Future game after LoZ:Wii comes out they should make it like TP trying to find three shards of something *twilight mirror has been reforming but not completely*,link has put the Master Sword back in the pedestal,went back to being a normal Hylian living with Princess Zelda in Hyrule Castle,but not forgetting Ordon,and is one day came to by midna in a dream to reform the mirror of twilight,etc.,etc.,etc.

omg i was so pissed off when she just left at the end of the game... like rly! just go make a sacrafice ur nto pretty

She will probably return in a later game and I think this because at the very end, while Midna was going into the Twilight Relm, she said "Link, I..." and then went on to say "See you Later" and then the mirror broke. I think there is something important she wanted to tell Link but decided against it, like another way they could meet. I say they could meet again because she says "See you later".

Just a thought.