Ultima VII could be good as a 3D title. The only problem I see with the idea is the Ultima games have kind of been out of popularity for a while. It's not a certainty that a 3DS reboot would regenerate enough interest to make the effort. But games like the Final Fantasy series and the Resident Evil series would almost certainly get enough interest to be remade.

Another old game I'd like to see a remake of--Pool Of Radiance. I owned both the PC and NES versions of this game, and if they were to remake it is a 3DS title, it would be good, just so long as they don't try to update it to v4 rules. Keep with the original ruleset but update the graphics and gameplay. Of course, like Ultima, it might be too old to be a successful remake.