I also immediately noticed that line when I read the Q&A but I'm still not quite sure if I like it or not. I think it's ultimately going to depend on how it's implemented in the game.
I'm honestly fine with having to commit to my party after Act 1, but considering it (apparently) comes at the cost of the game not having recruitable story companions during the later stages of the game is very souring. Something I always liked about older games was the possibility of encountering characters you could recruit to your cause even when you were significantly deep into the game. I know we'll get camp followers in place of party companions, but they just don't have the same kind of feel to them. Maybe I'll change my stance on this once I see how much you interact with the followers, but currently I think it's a bit of a shame that this announcement serves as an indirect confirmation that there won't be story companions beyond Act 2.
I think my biggest fear with this is that all of the different story companions will be located at the start of the game for you to pick up within the first 1 minute to 1 hour of your playthrough. I fully understand the logic behind giving the player a full party early on (both from a game design perspective and for the sake of the story) but I'm just afraid that picking up companions right away will make it feel as if they are nothing but an extension of the character creation where you essentially just customise your party right from the start. I'll have to wait and see how it plays out I guess.
