I'm gonna quote the golden rule of cinema here:
"Sequels Suck" (it also applies for videogames)
Any title with a 2 on it is just a desperate attempt to win more money. Grim Fandango is THE perfect adventure videogame (perfect story, perfect music, perfect graphics, perfect characters). That's something you just can't ask for twice. A sequel to Grim Fandango would be fun, but average.