It was confirmed, yeah, but who didn't know it was coming? John Carmack has been talking about all the improvements to the id Tech engine and how BA the next Doom is supposed to be for quite some time.
I'm hoping that the actual game will be good. I played Doom 3 was to see how the gameplay was (campaign was a HUGE letdown after playing Dooms I and II), and to see the engine. (id Tech 4 is amazing)