s, this is a better solution than the system almost every CRPG has used for the last 20 years. We've reinvented the wheel."
I think it has to be a technical limitation of their engine that only one character can ever be selected at a time, and Larian designed the controls around it. If that IS the case, all I've got to say is that Larian told us BG3 was a AAA game, with a AAA budget, and they hired up to build it. A AAA game dev would update their tech so it didn't cause problems that could only be solved with bad game design.
I don't buy the "engine limitation" excuse for a single second. And since I started this thread I even took my time to replay across the entire early access build specifically to check where terrain conformation would make the use of RTS-like controls a problem (at least, more a problem than it already is) and found virtually none. There are of course occasional "choke points" where the player will be required to do some minor micro management instead of just moving the full party in formation... But then again that's true even with the current system, which is also far less suited to that purpose.
Quite frankly I think that if Larian won't address this issue is because they just don't want to, because they are too stubborn about the alleged merit of their own Frankenstein creature and, as KingNothing said, they don't want to "kill their own darling". Not because they are facing any meaningful technical limitation.