I just have enough faith in the writers' abilities to assume if they fix an entire characterization arc, they'd adjust what kinds of reactions there are to it (I expect a similar amount of work/change if they were to finish developing Karlach's quest in Act 3 instead of just leaving plot devices for it all over the floor with no way to use them). But maybe that's closer to the big ambitious hope.
I think this pretty much answers my question from before. But we still don't know if devs/writers even aware of the problem and if they are, how they are planning to address it (if at all).
Best way (IMO) would be a rewrite that would fix issues with characterization and everything else discussed in the Shadowheart and Halsin threads and (hopefully) would make both players wanting open/poly and players wanting exclusive romance happy. But it is the hardest option therefore the least likely. Second best (for SH issue at least) would be removing problematic interactions at least from monomancers playthrough and all the missing characterization then could be just headcanoned - easier, therefore more likely. Doing nothing - easiest, but many people are left unhappy, because there are issues that can be immersion breaking at best or completely ruin the experience at worst.
Oh and there is still a chance that if they will go with a rewrite they will mess up something again and we'll be back at square 1.
This is why so many people argue for removing content that they don't like. Not because they are opposed to poly representation, but because it is most likely way to resolve writing inconsistencies, ambiguity and problematic interactions.