That's pretty much what I meant, and like yourself, I enjoyed Doom 3 as well.
I was going to say that it would be the most important iD game since Doom, or Wolf 3D, but nothing can be as revolutionary as those two. This is a more evolutionary step, like Quake was.
I have to say, I am slightly disappointed that iD only chose to broaden their horizons when they became more console focused. I guess a larger audience and better profits, plus entering deeper into MS's good books is good motivation -- not that I am saying there is anything wrong with any of those things.
But while I have noticed that a significant portion of migrated console developers have sacrificed complexity when developing for the consoles (with games like Rainbow Six: Vegas, Bioshock, Civilization etc) for various reasons, I have noticed that a few have actually made significant strides beyond what is naturally expected from new projects.
I just enjoying understanding all the factors behind these decisions, especially the psychology of it all.
For example, I really do wonder if iD would have taken such a bold step as they are doing with Rage, had they still been limited to the PC audience. Granted that they are very different titles, but I guess the success of open world games like Oblivion has something to do with it.