The thing is, although KARMA is promoted to be the answer to this, it isn't, really... at least, not for real live music. While it does add a quasi-random variation on any specific part, it doesn't really follow real world rules for that 'randomness'. In real life, musicians vary their parts with some pretty specific behaviors. It isn't 'random' in any sense of the word. And each instrument does different things idiomatically.

KARMA is a 'start', but there is much to be done before this begins to sound like real players. It's great for arpeggio's and the like, but I have yet to hear KARMA make a guitar part expand on itself and remain sounding like a guitar part except for the simplest of things.

My ideal would be to have a style where each part, each variation, was played first very simply, then very complex, and then the arranger figure out the steps in between. Then have that respond to whether YOU are playing very simply or complex (and offer an inverse function, so as you get busier, the arranger gets a bit simpler) and have it sort of go along with you.

In truth, many of our objections to the repetitive nature of arrangers comes from just how FEW of our styles do anything more than four bar loops (or shorter!), despite being capable of having them MUCH longer. I know Korg is one of the best at this, but so much more could be done. Imagine a 16 bar loop, where each time you fill, it could come back in at the 4, 8 or 12 bar boundary randomly, and loop from there, too... Not that difficult to program, really.

There are simpler, more MUSICAL solutions to be found than KARMA, I think.