The NES game sucked. But imagine a PS3 or 360 game GTA-free mission style game. The hacks in GTA with the Delorean show how good it would be. Here's a few.
http://www.youtube.com/watch?v=WyGb2yEgSG8
http://www.youtube.com/watch?v=xpj061MsDw8
That was, like, the most amazing thing I've ever seen in GTA. Ever. And I've done some pretty amazing (and stupid) things myself.
That would be cool. However, I think the ones for NES cursed any hope of ever making a good Back To The Future game.
they should...