his engines may not be used today as say the Unreal engine but he is a brilliant programmer and his code is still alive today, quake 3 code can be found in loads of engines still.
It's a shame that id haven't in recent times tried to harness this, it is sad that he has left id and it's a shame they didn't make the most of his skills in recent years.
Hah, Wolfenstein I know had it just the same. RTCW and Wolfenstein: Enemy Territory were some of my favorite games! I knew the quirks with the engine in and out too!
Anyway~ It's good to see him moving on to bigger and better things. id hasn't been something I've looked towards excitedly for quite sometime since well... Quake Wars was a flop. Was again disappointed when they left Raven Software to handle the last Wolfenstein which was a bit of a joke...
Oculus Rift is gaining traction, and I fully support him being on board with it.