I'm not being argumentative or want to be. But your suggestion of a fix, "Cmd Z," doesn't fix anything, it simply reverts. In using the custom point curve we are purposely making a needed adjustment that needs to remain. The thing is, getting to that needed adjustment is extremely difficult (I am wondering if we are discussing the same problem.)
Adobe will assess each bug using a range of criteria. If it crashes the program or requires Lr to restart, it'll obviously rank higher than when users can simply undo their way out of the problem or re-apply a preset. How often users encounter it, how easy it is to fix - those are probably other factors. But their actual criteria are very hard to discern, and I can think of at least one stupid bug that hasn't been fixed since version 1 (on Windows it fails to display the full keyword list if you have a list of >2000 keywords). Here I've no feel for how easy it will be to fix, but the bug doesn't seem too painful - for most users. For you, obviously it is.
What does "fixed in due course" mean? We've had this problem since September with the release of Sierra. In that time I've taken thousands of photographs which have needed to be imported first into ACR, made custom point tone curve adjustments and then import those same files into Lightroom. Is that a new Adobe work flow?
By "fixed in due course" I mean it looks like they are acknowledged and I'd be surprised if these bugs aren't fixed in the next dot release.
Given my assessment of the their significance, that seems reasonable. I just don't think most Mac-based Lr users will be greatly affected by the tone curve bug. Maybe you have a special reason for applying custom point tone curve adjustments as a matter of routine, as you imply. But if someone came to me and said they were doing this, I would question such reliance on the tone curve. I have certainly encountered plenty of people who learnt Curves in Photoshop and carry this practice over into Lightroom, largely overlooking the Basic panel and trying to accomplish everything with the tone curve. But maybe there is some special requirement?
PS You mention the Ref View feature which I never use, so to me issues with that mean nothing.
There aren't issues with it - it's a really good new feature that, for almost everyone, makes it worth upgrading, which is what this thread is about.