and quite frankly it doesn't really look like Larian cared a single bit, so I'm not optimistic about things changing at this point.
I still choose to believe. I think current system simply doesn't work - I doubt many players engage with it, and as such it needs a change. With how hidden reactions are in new UI overhaul, it either means that Larian completely gave up on making reactions work, or an overhaul is coming and they didn't bother to implement reactions nicely into the new UI.
Sven did say that they are working on some form of reactions overhaul, and while I don't expect it will be precisely what I wish for it to be (which is pretty much what the post you quoted described - Solasta but with high production value and no crappy, poorly placed yes/no boxes) I still hope that something wil change.
Like with "swarm ai" development might take time - it's just frustrating that Larian isn't willing to communicate in more detail what they are working on and stick to "we will show it when it is ready".