I'm not sure there is such a big difference. While exploring, companions in BG3 talk to each other very often, unlike WotR. It's hard for me to consider saying literally one sentence as a conversation, as is the case in WotR, especially since many of these "conversations" are written so that they could fit more than one person. What WotR does better is that the companions join the conversation. Only here are two things to consider. First of all, considering the whole game is a bit unfair. We only have less than 1/3 of the game. Secondly, full voice acting is quite expensive so of course there will also be a more limited number of combinations. It would be nice if companions joined conversations more often (it's much better than it was at the beginning of EA), but you shouldn't have unrealistic expectations.
It's not comparable. I participated in WotR alpha and beta too. If the current state of BG3 is 1/3rd of the game, then WotR up to the end of chapter 2 is basically 1/3rd of the game there as well. By the time you get to the end of chapter 2 of WotR, you already have a very clear idea on how most of the party members feel about each other, and they've all interjected in conversations numerous times. BG3's companions can talk while exploring, but I can't recall a single one that didn't go beyond mildly generic quip about where they're from or what they do, nor do I really learn anything meaningful about the characters involved. With one exception, the heavily scripted one near the ruined town involving Wyll contacting Mizora. WotR's equivalent of exploratory banter would probably be the campfire convos, a good chunk of them being voiced.
I think the point I'm trying to make here is that the primary difference is that most of WotR's companion convos lean greatly into their personalities, sometimes showing a level of thoughtfulness towards each other, instead of somehow looping back to their personal plots or backstories. Because you should already know enough about the latter from meeting them, talking to them privately, or from their personal quests.
Stuff like this is a subtle way of livening up not only each other's personalities, but the setting they're a part of. While BG3's companions still feel rather self-contained.
There's really no reason to believe that BG3's companions can't reach that level of interactivity or complexity. Maybe you're right that this is an unrealistic expectation. Doesn't mean that there still isn't work to do in this department, especially considering we only have 5 companions right now.
Looping back to what I said about DOS2 before, there was a huge amount of missed opportunities with the companion cast in that game. Sebille and the Red Prince had brief animosity towards each other at Fort Joy, but it gets immediately dropped and never brought up again after the first step of their personal quests. One would think Red Prince would have something to say upon Sebille remembering that she's basically next in line to become queen of the Elves and royalty just like the Red Prince is. But nope. Ifan doesn't seem to react to this revelation either, despite half of his personal quest dealing with his immense guilt with near genociding the Elves by indirectly gassing their homeland with deathfog long ago. And that's just the things I can think of as it directly relates to their personal arcs.
I really think that BG3's cast is capable of so much more. Quite frankly, going all in on the banter would be the best way to dispel the commonly held notion that they're all rather one-note, in their depth largely consisting of their shrouds of mystery and not much else.
