Things we know about the new game, from KME:
1. It will be story based rather than a mishmash of events.
2. It will have an upper flipper,
3. It will have a mech that "changes state", a single shot that physically changes as you advance (like the ramp in IMDN or the castle in MM)
4. It is coming soon, probably next.
5. He is already working on game #3