Gamasutra reports that, when asked about his freshman effort, Mechner replied: "There actually is a plan to bring back Karateka. It's a project I'm going to be involved in." Just to make things mysterious, he added: "I can safely say it's not going to be in the way you expect."
We'd expect a 3D reimagining of the side-scroller, which is best remembered for its (at the time) stunning animation. We wouldn't expect an RPG, FPS, RTS, or MMO. Hey, maybe it will be a Karateka FPSRTSMMORPG? Actually, lose everything but the "RPG" (think Jade Empire) and we may have a winner.