I doubt they will do a lot of changes or give us new scenes.

If we are lucky we will get
- Bugfix so that his clicky dialog is restored in game
- Bugfix so he doesn't interfere (unwanted) with other romances in game (I guess it is a bug but who knows)
- Bugfix/Change that we get a dialog option in the end scene that we can leave with him together

Everything else would be great but I highly doubt we will get more.

For me personally the romance ending if corrected would also help a lot with his romance in general. Poly or not, if you at least in the ending get the impression he really wants Tav included in his future and not just for sex it makes it something to look forward too. Right now I have little interest in finishing the game due to the ending with him. Instead I am tempted to break up with him and go for the romance with a certain character in act 3 where you at least get the option to stay together.

I mean, I can do a lot with head canon. But his ending feels just so disappointing - every other romance you can stay together with, under certain conditions at least. But not with Halsin. Yes, he says you can visit - but VISIT basically means come and say hello, have some fun together and off you go again. Nothing about STAYING and building a future TOGETHER. Poly or not - this option should be possible.