I think it is important to state that this is an attractive option mostly because of BG2 and it's pretty deep party interaction system. Even in BG1 party banter was rather minimal compared to BG2. BG3 does not have that. Interaction is basically a one-way ticket between the PC and one companion. Also most games do it like this now, it is simply cheaper and easier to do it this way, plus it adds replayability, which is all the rage since quite a few years. Mass Effect only allows two companions and in DA, as others pointed out there were only three as well. I think Neverwinter Nights also only had 1-2 companions. So having two more people in your party was nice in BG2 where you had all the interaction, but yeah in BG3 you would have two additional mutes that would only contact you if they had something to complain or needed help with their personal backstory. With how polarizing the companions can be at the moment, I do not think this is a stellar idea. On the other hand, if they choose to go the route with better written and more written characters basically, I am all for it, because replayability means nothing to me and never has. I might replay games a lot, but I never really play them differently. In fallout I am always the ranged stealth dude with a hero complex. So locking me out of content because of party limits and killing companions of, means I just never see that content. So in this case, Astarion might have a great story arc to him later, that I will never see.