I don’t have to know something about Cubase in particular. I’ve been a software developer for 16+ years (CS degrees et al). What I’m saying is based on how things work with software in general. I understand that they might have some code inexorably tied to some OS APIs, to the point that it’s very hard to fix it. But if that happens while other 5 DAWs with the same functionality work just fine, then it points to either “technical debt” or them doing something very special that those others don’t (and I don’t recall that there’s any completely unique functionality at that level).
And again, that would understandable. It’s the “no communication” / roadmap / “keep users in the dark” thing is what’s troubling. That’s what makes Logic users worried about its future, for example, when new versions stall and nobody knows if they will even ever land.
Also troubling is the “don’t bother testing and starting thinking of a fix when the betas are out, we’ll do it only after the final release”. If that indicates lack of resources (instead of indifference) that might make it understandable, but it doesn’t make it any less worrying.
If that was the case other DAWs would have hit the same snags. Paths were a userland app has to talk to the OS and underlying libraries are not that many – if Live, Logic, Pro Tools, BitWig, Studio One, and can push audio, sync, draw their GUIs, talk to MIDI and record, so should Cubase.