I used to like the old Roland system of three buttons for Bass & Drums, Small Combo (Bass, drums and the comp, either piano or guitar), and full style.

I think most arrangers could benefit from this...

I'd also like to see a system that allows you to use Markers in an MP3. Obviously, this is quite a complex task, as a bar/beat map would have to be generated so that the machine knows where the 'one' is to jump to, but it's a VERY useful feature for SMF's, and would be equally useful for audio files.

While we are on Mark/Jump features, it would be handy to have each Mark point store a 'loop length' parameter, and a double tap of the Jump button would make the sequencer loop that section until you single tap it, upon which, it carries on (or you tap another Mark point).

I'd like to see a change to the arranger's screen display background colors (maybe a nice red-ish hue?) for when you are transposed... I have a bad habit of forgetting to take it off at the end of a song, and start the next song in the wrong key (the G70 transpose button is well off to the side, away from the main display)! Something in the main display that you can't miss would help idiots out like me!

I think that the Kronos's SSHD streaming of samples is the future. 12GB instead of less than 1GB of ROM on a current arranger. This should be adopted immediately!

Pianostyle mode should have a user defined number of notes before the new chord is recognized. Sometimes three is a bit too touchy. Four or five might make for a better, cleaner recognition...

For Roland's (who still don't have a Break/Fill, just a Break/Mute) I'd like to see a Fill hit during the Mute play ONLY the drums (nice little pickup opportunity). I also like Ketron's separate Break/Fills for each Variation. The Break that works for Var4 rarely works for Var1... (I know, I know... I am getting past arranger features that NO-ONE has, but this one is pretty good, and nothing else has it, AFAIK).

Come on, keep 'em coming...!