FPS fans were rocket-jumping with joy yesterday at the news that Id is working on a new 'franchise' (game), not based on Doom, Quake, Wolfenstein or Commander Keen. "It is a new id brand with an all-new John Carmack engine and I think that when we show it to people, once again they'll see, just like they saw when we first showed Doom 3, that John Carmack still has a lot of magic left-- Id working on new IP [Guardian] via GamesIndustry.biz.
I was just contemplating a bit on this on the car ride into work. Comparatively, three of the major developers of the FPS genre have very distinct difference. Epic has always attempted to cram loads of gameplay, often feature more gametypes than anyone else (although they're trimming for UT3). Valve doesn't seem to like to develop new mechanics - but they know them when they see them and attempt to box and capitalize on them (Team Fortress, Counter-Strike, Portal).
Id seems to still be riding high from the days when Quake was the deathmatch of the day. Despite some promising concepts (like using light and shadow) - Doom III remained a mostly solo experience. Enemy Territory has really taken the mantle of pushing online mechanics for their franchises.
Course, I think some of this is that Id still has a very traditional approach to mods. They have an almost Prime Directive nature to their philosophy - provide tools but don't try and meddle with the community. As such, Quake III probably had more pure gameplay mods than anyone else. Id got used to producing the core and letting others run with deeper, more expansive game modes.
So if Carmack and crew are getting outside the box of Wolfenstein, Doom and Quake - what will they do?
Safe money is something along the lines of what we saw with Doom III - a mostly single player expedition to showcase whatever tech wizardy they've been compiling. Which would be fine, but I'd much rather see id try and get way outside the box and start trying to innovate not just on rendering and shaders ... but mechanics as well.