Hi,
As a keyboard player who often has my hands on more than one synth at a time, it makes sense for the controls to simply require one hand to operate and leave the other hand free for playing keys. Changing banks is one such example, and I don't mind it so much as I'll rarely use more than 10 sounds in a live set anyhow.
The place I think there's room for improvement is with the transposing of the arpeggiator. I love that you can transpose the sequence as it's playing, however I would much rather be playing another synth than holding the record button down with my free hand in order to do so. Wouldn't it be nice to hit the record button as the sequence is playing and get a flashing light that tells you it's in transpose mode? hit it again and it returns to play-over mode?
Another (preferable) solution could be to use the HOLD button as such a toggle as the sequencer plays as the hold button is fairly useless whilst a sequence is playing anyhow. The HOLD button makes sense to me as it's right there by the keybed and can very quickly be switched to toggle from transpose to play-over mode.
I have no idea as to whether or not this is something that would be possible to modify through a firmware update. I just thought I'd put it out there and see if anybody else has any thoughts on the matter.