I think they chose this model for two primary 'reasons.' One, issues/timing with CMs and changing CMs. Two, this game is more polarizing than their previous games have been. I said it very early on and was mostly ignored, but they've chosen to take on two new target audiences with BG3, and the three audiences they cater to are unlikely to have any unanimous agreements. Simply, point two is that they feel they can't get work done if they just place themselves in the crossfire. It's a double edged sword, but players aren't to fault for their choice to take on the BG IP.
