"All those arps makes it look like the Motif ES is designed especially for people who want to hold down chords and let the keyboard do the walking."
Deja Vu for Karma users. Stephen Kay, the inventor of the Karma architecture, designed for himself. Although an excellent keyboard player, there were things he wanted to do but could not--like play convincing harp glissandos. The result is a pattern generation system that allows real-time continuous control over patterns, something that few arranger keyboards provide. I think of the Motif as a step in the Karma direction, providing skilled musicians a way to do things they could not do otherwise and offering them a level of control not normally available. The fact that these keyboards also allow novices to sound ok is just a side benefit.
In the Motif ES video, I though the use of the velocity slider to control megavoices in an arpeggio showed that the Motif ES aspires to be much more than a conventional arranger.