Yes indeed, that's the same Warren. He started as an editor at Steve Jackson Games in the mid-'80s, where he was my boss on Space Gamer magazine. We wrote Send in the Clones together in 1985. Warren moved to TSR in the late '80s, where he helped manage the design of AD&D 2nd edition. Then he went to Origin, where he produced many hit games.
After a stint at the Austin, Texas office of Cambridge, MA-based Looking Glass Technologies (later Looking Glass Studios), Warren started the Austin office of Dallas-based ION Storm, where he designed and produced Deus Ex. Warren has recently started his own studio in Austin. Details remain obscure. He says it's weird to see his old PARANOIA work back in print after so long.