Mario,
I believe PGM has enough of MIDI content, just most of it is not very usable because of workflow limitation.
Specifically, I am talking about individual instrument parts of huge library of PG MIDI styles. These are nearly impossible to extract into individual instrument tracks that can be mixed and matched like RT, RD and Super Midi tracks.

On top of that, many 3rd party MIDI pattern / loop libraries cost close to nothing. It's BIAB workflow that has issues/limitations with properly integrating those into composition.

In theory, you should simply be able to audition midi pattern or midi loop in a picker, place it on a track of your choice and it should follow tempo and chord changes without doing crazy acrobatics. If we are on the same page, it is a workflow item.