DOOM 3 just doesn't look as "alive" as HL2. Some people won't care about that. I do. I've been looking for a game that brings the world more to life instead of just making it look prettier
Go play a different game then, what do you expect from a company called ID? They're games have always been about the "darker side" of things. Personally I love it, I hate all these games that try to bring the world more to "life" If I understand you correctly. As far as I'm concerned it's all about the gameplay and atmosphere and If it's dark and dead, so be it, It's just an experience to be appreciated on it's own, like looking at a painting, you don't look at a painting and wish it to be something else, you see it and you either choose to experience it, or you don't like it and move on.