I will be happy if Yamaha makes an expandable arranger, but I am not that excited about the expansion options. The VH-vocal harmony and XG are built in. The piano should be. I do not really care about the DX, although format synthesis might be fun to explore. Maybe the analog modeling would also be. I have an MU100R and like the VL physical modeling synthesis. However, to use it to full effect requires several controllers that may not be available on a given keyboard. Also, a separate interface is required for both access and for programming. This is a lot of work for one extra voice of polyphony. If it were Korg's MOSS explansion board with 6 voices, it would be more worth it.

Roland's expansion system is more practical. You do not have to learn a new operating system for each plug in. While they just may be new sounds, I would love to add "world", "Asian" and "Choir" to my arranger.

What I really want to see is two generic memory expansion slots like those used with digital still cameras. These could be filled with pre-programmed ROM or programmable FLASH memory. The memory should be useful for storing styles, sounds, or whatever the user wants. I would have a USB port that allows an external floppy to assist data transfer and for operating system upgrades. I think we should get away from keyboards with disk drives built in. If a hard drive is needed, make it external or use IBMs microdrive in a memory slot.