While I doubt that it will revolutionize gaming as a whole, I would not be surprised if it revolutionizes first person shooters.
Personaly, I began playing Halo on the Xbox a couple of years ago, and it is still, to this date, the best XBOX game IMHO. On the PC, what can I say? Net code is bogus and the team behind it did a very bad job. The same with the overall port... somewhat of a letdown, but in terms of graphical quality, if you have the right machine it will look good. As you said, not as good as Doom3s.
Unreal 2004, while a good game overall (I barely began playing it last week), it is a much better game in terms of the way it was coded, and even the crappiest PCs can play it.
While I agree that what has been shown of Doom3 isnt anything stellar compared to the other games that are coming out, you have to keep in mind that it has been several months since we last heard or saw anything of Doom3. Much could have been done to improve it in this time of absence (close to a year I believe), and dont forget that Carmack has never let anybody down so far (in terms of his games).