Oh, I wish there was a continuation of the Sonic Adventure series from the beginning of the decade. Sonic Adventure and Sonic Adventure 2 were so amazing I wish SEGA made a third game for that and still retained all its important features... like the Chao Gardens and maybe the Adventure Fields and such. So much fun
I'd love A jet set radio sequel most and foremost!
I'd also love to see a proper and polished Mirror's Edge sequel with open world elements. A game like Mirror's Edge deserves exploration and needs to reward players for doing so. my dream game would be a mix of Mirror's Edge and Deus Ex Human Revolution
It actually depresses me when I think of the lost potential of Fable. If I could have one thing, it would be a remake of Fable series the way it should have been. 2 and 3 were wasted, a fantastic vision extinguished by a fool.