Probably some organs, a harpsi, a marimba, sawtooth lead, et cetera...:-/[/font]
maybe Distortion guitar too
Various Timpany drums in the precussion section would be excellent.
If the ?synth experiment thing were to be added in as a regular instrument, that'd be great...
But anyway, some kind of flute or ocarina sound that worked like the synth thing would be really nice, instead of only being able to use the smooth synth for longer notes.
Flute will be good as a instrument that'll replace vocals on some music.