We have had audio loops in arrangers for well over ten years. We have also had them as non-realtime elements in BIAB and general audio production for years. Lionstracs was the first to do more than drums if I remember rightly.
There’s only one NEW solution to changing notes within a chord in an audio loop, that’s Melodyne. Which isn’t real-time, and isn’t obviously part of the Event (or it would have been the first thing AJ and you would have said). There is no getting around the obvious, and I certainly don’t need to sit down at an Event (which in my area means basically never, there's no Ketron dealers anywhere near me!) to know, if you haven’t recorded a guitarist playing a diminished chord, there is no way whatsoever that you will still have a live guitarist playing that pattern in the style.
You have the chord choices that Ketron recorded the guitarist playing, however many that may be for each style. And that’s it. Period. No ‘you’ve got to try one’ BS.
It’s quite simple. If you currently have an Event sitting in front of you, solo the guitar part, and play a chord progression like C - Eb(dim) - Dm7 - G+7. Post the recording. If you want to claim this is not an issue, let’s hear it…
The proof is in the pudding.
_________________________
An arranger is just a tool. What matters is what you build with it..!