But for people like me who play RPG's for rich character progression and story purposes, it enhances a lot.
I am an RP whore, I will take weak game play with great RP any day. When I think of "great" RP though I do not see that in BG3, good for sure just not great. When I think of a CRPG and relationships I image something like Drizzt and Belwar. As their friendship grew they became very synchronized in battle, from a game mechanic point of view this would be a special move they could do when together. I also image the deep friendship, with snappy banter back and forth that would increase as the relationship grew.
I do get how romantic relationship an evolve but even those should add something to experience. Image having a deep relationship with Karlach and if something happens to your character, goes say under 25% health, she goes berserk. Going out of the player control as she attempts to demolish any enemy attacking the PC until the fight is over. In this way the relationships, in my opinion, would feel deep and meaningful. Way more so than a quick sex scene and a couple of cut scenes of soul baring.
BG3 has some great dialog and writing. However it feels like they said here is a cinematic and then let is drop.
Also to me the RP is limited in that if you want to pursue a deeper relationship with a companion it has to go sexual. There is no way, again using Drizzt and Belwar as an example, to create a deep friendship, any attempt heads straight to courtship and sex.