Musocity,
The list you refer to is solid. I was pleasantly surprised to see Ueberschall mentioned. Difference is it was offered without sarcasm.
Absolutely BIAB (and plugin) need a lot of things done to be whole. But... I believe the priority should be given to items that must be done (VST3 for example), known bugs and limitations addressed and unfinished features completed with aim to improve workflow, getting rid of redundant methods on the way. And when BIAB is slimmer and smoother think of other features to add.

Most developers, when come up with a new feature that supersedes existent, get rid of previous method. In my view, redundancy is the biggest issue with BIAB. They spend enormous resources of time tackling bugs, many of which are related to redundant methods, instead of spending that time focusing on coherency and workflow.

BIAB is a very capable software, but time is ripe to invest in maintenance and 80k mile tune up.