as far as we know at the moment, more wave rom, and space for more add-on sample boards, with the existing sound cards also being suitable, ie the implication being the new samples are not already on the existing upgrade boards, and new upgrade boards for the future.
At Frankfurt they talked about new organ samples that include classic organs with the tab system in the screen, in the same way you have drawbars in the screen now.
The main new areas will be direct digital audio output via usb (no analogue stage needed from keyboard to pc hard disk) and flash memory card expansion for instant load with no hard drive spin up time, also a file transfer system via usb, and ?wave? and ?mp3? audio playback from flash memory. The detail we will find out in a couple of weeks.