I think CMG "just imported" to Capcoms code to P-ROC. That would mean some details must be proven and re-programmed.
Change the code to connect with RGB-Leds. Thats it. For sure a lot of work but not completely rewritten.
However ... my homemade BBBr runs very well. For me the software is , at least, nearly finished and good playable. My homebrew KPr its more tricky. The software is far away from "ready". Several dots are missing and the missions are playable but on a ball loss you will start the last mission again. I am sure, this is a bug and not a feature.
Good thing: (Not only) in the german community several people are able to programm WMS code. *IF* there is already WMS code for the BBB adaption, this might make living much easier to "redo" the software on WMS platform.
What I like on all WMS and Capcom original titles: You boot and 10 seconds later you can play. On P-ROC and all newer Computersystems you boot ... and it tooks very long until the boot is finished. In the old days we were talking about some 100 kbyte code, new games need Terrabytes
I am looking forward and have the feeling that there will show something up in the future !