More complex than what? An audio guitar loop isn't so complex that it can't be done. It is being done. It's just as likely that this technology will be available as soon as or sooner than the gigs upon gigs of streaming memory that it would take to do all the chords for all the styles as actual audio.
BTW, have you worked with the new DNA to see how limited it actually is? Have you seen or heard any user demonstrations of it not working very well?
Melodyne can pretty much do it in realtime. You can play a polyphonic piece of audio and change the notes of it via midi keyboard in realtime. Yeah, Melodyne has to take an initial look at the audio first, but that could be done in the arranger too, so it already has looked at all of the audio loops and knows what's in them when the unit ships, so then it can just start doing its thing as you play.

Sure, it won't be in the next generation arranger, but I'd rather see things go that direction than try to get players to record actual audio of every chord type imaginable for every style, and still try to make it musical.

How long ago was it that we were impressed with Vienna orchestral having the ability to do realistic glisses, slides, even note to note transitions? And now we have super articulation 3 built into a keyboard that is doing just that. 5 or 10 years sounds about right.