gary,
It is true - the MS40 was way less complicated to operate, but remember, it also had way less features!
With the AUDYA 4, you can (by simply pulling down a slidder - chords) take out the manual chords being heard when you play with the accordion, or by pressing the MANUAL BASS, play the bass manually while the Arranger Bass is instantly mutted; still relatively easy, just with a slidder rather than buttons!
What issue(s) are you running into outside what's mentioned above if I may ask?
Thanks,
AJ