well it says it would be "nice to have" but is not a primary objective. But since the only thing stopping an A1200 mobo fitting in an A600 is the mouse/joystick ports, which could easily be replaced by headers and ribbon cables (which later revisions do for the first mouse port), unless Jens is planning to use that circuit board real-estate for something else i don't see why not.
yes. if it does more things than exist before that would be good. it's what it won't be able to do, out of the box, that an existing A1200 can do out of the box, that concerns me.