I feel like doing it that way only adds an extra step, because then people would do the roundabout way of having multiple BG3s open, selecting the origin characters, and then recruiting the three remaining. Just letting 7 there would allow the same effect. Though personally I find 7 to be that amount that starts to tilt difficulty too much, but if other people greatly prefer it, I wouldn't feel bad about it and instead work with 6 characters or try 7.
Err, essentially my philosophy here is too many is way better than too few.
