I think it is definitely time for Korg to adopt the four fill system from the PA3X into ALL its arrangers. It is long overdue, Yamaha and Roland have had this for at least 8 years or so...

And while they are at it, how about the Chord Sequencer?!

TBH, at least on AUTO-FILL, there really isn't any reason why the OS's of the mid-price line couldn't be updated to allow for the extra fills. But I imagine Korg would make more money bringing out a new model.

Maybe not with utterly new features that other arrangers don't have, but when you are playing catch up to even low end arrangers from other manufacturers, I don't think it pays to restrict something like the 4 (or 5 if you count Break/Fill) fill system to ONLY the TOTL arranger.