Truthfully I don't even think simply changing the character that is speaking goes far enough. Nor, indeed, should it be as simple as 'just add all bonuses to whoever is speaking, regardless of stats'. Either of those is perhaps fine for solo player, but in the case of co-op it becomes unwieldly. I'd much rather see a SWTOR-like system, where every dialogue choice is a vote, and then whichever wins is spoken by the character that voted for it. This is a MUCH more natural form of dialogue that involves all of the characters, and doesn't leave anyone feeling left out. It also encourages some different skill spreads.
The current system, regardless, is not a good one. It was a problem in DOS2. It technically worked, but it was incredibly annoying and we were forever reloading and trying to get the persuasion character to be the 'talking' one whenever it was relevant. DOS2 didn't have a TON of these, so it was mostly a problem with 'forced' dialogue cutscenes after bosses or walking into an area. BG3 is liable to have MANY more skill checks, however, and we shouldn't feel the need to simply have one person do a lot of the talking or constantly save scum.
Sure, D&D often has a 'face'. But some things are better enhanced by the medium we're playing in when the options are there, and a SWTOR-like system would do it.
