I've flown the B733 a few times since this conversation started back up. Even without any updates, I found the Vnav and Lnav to be incredibly stable. The aircraft, even in its current state, is a lot of fun to fly. There's no harm in giving the developer a gentle nudge requesting the status of updates. The harm here is accusing the dev of completely abandoning the project, which, in my understanding, is not true.
In my years of living, and trust me, I've got many years under my belt, I've found that I can generally catch more bees with honey, rather than vinegar.