Full amount of instruments in mixer (independent from style)
In my opinion it is no good idea, to limit the possible mixer-instruments dependent from style. In standard style 'medium swing' e.g. one has only a very weak/silent bass option. One has to lower the piano and the drums a lot for noticing the bass playing.
I see no sense in this limitation, specially as there is the 'Standardinstrument'-reset button.
(It seems, this wish exists always for a long time. Pity that it didn't get realized.)
Interchange of instrument comping between styles
It would be very interesting to be able to use the comping pattern of some instrument in any other styles.
For ex, I'd like to use the "Long notes" jazz style piano pattern for the latin cha-cha style, because I feel the cha-cha piano pattern is too syncopated (and too busy), and overuses montuno patterns. If I could use other styles piano comping (such as bossa nova or jazz long notes) in the latin styles, that could expand the styles possibilities.
Ukulele instead of Guitar
I would like to hear the ukulele in the list of styles, which have guitar in the set of instruments. Imaging "Over the rainbow" with ukulele! This would be wonderful. :):):)