Eternal Darkness... that would be kool!
and a pokemon stadium wold be also kool!

Lost Odyssey and KotoR 3 if it counts

Xenoblade.

Such a truly amazing game, it would be a travesty if there isn't a sequel, or at leaat a game like it.

Sure, the ending suggests otherwise, but there's plenty of planets out there...literally

Sonic 3 (if S3&K is viewed as a continuation)

Oh, and the pre-EA Command&Conquer games.
(worthy sequels)

I see a lot of great names on the posts here! Some more games that I have noticed while looking at my collection...

A proper sequel to Alundra (or maybe one to Dual Hearts, which I consider a spiritual successor to Alundra)
A proper sequel to Brave Fencer Musashi
3D Dot Game Heroes 2
Just Cause 3
Mercenaries 3
Billy Hatcher 2
Cannon Spike 2
A new Jumping Flash
A new .hack series
New Champions of Norrath
Dark Cloud 3
New Jak & Daxter
New Klonoa game
Rogue Galaxy 2
New Shadow Hearts game
Warriors Orochi 3

MIRRORS EDGE! Hopefully Dice will work on it after Battlefield 3 using the frostbite 2 engine. I'd want it to be one of the last great games on current gen. And then the next battlefield can be made for next gen :p

Battlefront 2. D:

Eternal Darkness. There is SO much more they could have done with the story/sanity meter/magic system, etc. Such a shame..

We can dream.... only dream :(