Should this game be RTWP I would say Yes it should have been and the reason is simple Baldurs Gate 3 Not D:OS 3 tabletop does not come into this because they made a statement this was a successor to the franchise so that comes with some expectations and one of those would be a playstyle But it would have been = acceptable to include both
To be honest I don't think Larian Engine was the right to create a spiritual successor to BG franchise I actually think Owlcat games would have fitted the bill more as their unity engine with their modifications is what I consider to be a modern take on infinity engine. All tho who to say if Larian Engine can be changed but until I see Larian engine as an RTWP this is only a hypothesis
I am not knocking Larian here as the game they're making could have been a new franchise on its own for Larian but they brought Franchise name to Baldurs Gate and that comes with certain expectations.
But again This game I do feel has the potential to be a masterpiece of its own and I actually think the name they took damages it.