if Quake was ever to come back successfully as a series, id needs to do a remake of Quake1 based on the H.P. Lovecraft universe and whatever bizarre stuff they could think of.

fuck your space marines, fuck military design, fuck mad max-ish post apocalyptic settings.. the FPS market had enough of this crap. Quake2 had its sequel with Quake4 and Rage already seems passé. it's time to go back to the originator!

to capture the minds of gamers again, all you need is a top notch grisly visceral atmospheric singleplayer, like a really fucked up nightmare.. and have an old school arcade carnage multiplayer on top.

there have been so much COD clones, the genre practically begs for a breath of fresh air.. although people might no realize this since they're spoon fed with only a few recipes of FPS games.

to end this useless rant, you might as well even ditch the Quake name. it's terrible to begin with and has no brand awareness outside of hardcore PC gamers. it was used in a stupid way as an umbrella for a series of shooters not really related in a consistent way.

PS: there is this Quake1 remake attempt with the Doom3 engine. it is pretty decent, give it a try: http://www.doomwadstation.com/doom3tc/quakemod/