The good thing with baseflight is that it exists and is working. To my knowledge it is the only fork of MWii that has made it into a working flight controller project and for some time too.
that is all being done now. Up until now, he has done
yes, that is part of what I call a problem in the long run. It _needs_ doing, because it is separate forks.
he updates just what he likes
yes. So not all features from arduino-mwii make it into stm32-mwii. Last I looked the entire LCD & telemetry stuff was not there.
Besides, there is no 'backchannel'. New features from the stm32 fork have no designated mechanism to become part of the arduino-mwii in an orderly fashion.
That's all rather typical with forks and it is one of the reasons I'd rather see one multi platform MWii source.