Mario,
"OR PGMusic could keep it as it is now and add another 16 track MIDI/RT/RD I/O."
+1 on that

P.S. Probably it would be cleaner to do this as "tracks on demand" (add as many as you want, with reasonable limits) or even project templates.
Michael,
I feel your frustrations as I too have issues bringing some midi arrangements to BIAB from other places and as soon as I do...I got to take couple of advils ahead of time. Going out to Cakewalk another 2 advils.
I am curious, what kind of laptop you have? I tried 2018 BIAB on a 8 year old, i5 laptop, it worked fine...