No - dont bring that guy back. He's dead. I dont want dead guys coming back. Also, Quaritch was only the figher, the "evil villain" was selfridge (or rather the RDA).
But I'd like to see in the sequens, that something good comes out for humans, that they end up "seeing" and acting. I leave that open, but I'd like people on Earth to follow Jake in their own way and create a new future on Earth inspired by the NA'Vi and what is on Pandora. "They killed their mother" - thats what Jake said, and I would see a scene in the end where a little seed of the sacred tree is growing on the desolate plains of that Earth with the knowledge, that this can be a new beginning, a rebirth.

- well , just fan fantasy