I personally would love an arranger with 88 gha keys, for instance the Fatar TP40GH-ES.
Styles that are as good as Korg's (I personally feel these styles are more balanced and a bit more modern sounding than yamaha and roland, but that is my preferance)
Multi layered samples, like Megavoice or RX technology to make the styles come alive!
A real piano mode, where the autocomp follow the bass notes, the root note of the base should trigger chords. If a third is not specified the comp should play 5ths, or retrieve the third from the right hand.
Give me a good control surface, and a touch screen
Take out speakers, metal frames and all that extra weight, and give me all this in a sub 30lbs package
I would buy that board in a heartbeat!
Doc-Z