I think the first was a mediocre movie at best, and pretty poor in comparison to the better games in the series (notably '2').
I think if they make a second one it should run close to the games be darker, more claustrophobic, etc...
I think the most enjoyable aspect of the first one was the commentary on the insanity that is organized religion, which was one-upped big time by the psycho-bitch in 'The Mist'.