I think the problem is that Larian has made its brand with the motor it used for the DOS, wich had a really awfull movement system both with the controller (I play DOS on PS4) and the mouse-keyboard.
Still they made their name with those two games and so they landed the big contract: to make the third act of a D & D based rpg that is considered a milestone in such games, the 3rd chapter of Baldur's Gate.
Obviously they're going to exploit the motor they used in the games that became their brand. I just hope they'll take account of the criticism (is annoying to have to make jump the characters one by one et so on) and try to make the movements more smooth and that the story will be engaging like that of the Baldur's Gate of the days gone or the two DOS.
The bigger game, with the bigger budget is their opportunity to make that "motor" better. To improve systems they didn't have the resources to do right the first time(s) around. Larian themselves straight up said BG3 is a AAA game with a AAA budget, and they staffed up and expanded their studio to make it. There's no excuse not to improve their tech where it's weak, and it's weak in the area of party controls.