Design work on an alternate game has been going on in parallel with the mission pack development and my research work.
Several factors, including a general lack of enthusiasm for the proposed plan, the warmth that Wolfenstein was met with at E3, and excitement about what we can do with the latest rendering technology were making it seem more and more like we weren't going down the right path.
I discussed it with some of the other guys, and we decided that it was important enough to drag the company through an unpleasant fight over it.
An ultimatum was issued to Kevin and Adrian(who control >50% of the company):
We are working on DOOM for the next project unless you fire us.
It wasn't planned to announce this soon, but here it is: We are working on a new DOOM game, focusing on the single player game experience, and using brand new technology in almost every aspect of it. That is all we are prepared to say about the game for quite some time, so don't push for interviews. We will talk about it when things are actually built, to avoid giving misleading comments.
Further along, he mentions that Paul Steed has been fired (John says he did a damn fine job as modeler, but was fired because of the whole event, kinda nasty). Be sure and read the entire update, pretty damn interesting. In addition to that, you can read what former id Software employee Zoid has to say about it here.