It's cheaper because they only have to focus on 4C4 (4 choose 4) dynamic dialogue options at a time, not 8C4 or, like BG 1 and 2, 18C6.
This is basic logarithmic math.
never mind, you deleted your post.
I am just waiting for the other shoe to drop and they tell us "we can make the Origin characters whatever class we need" ... #puke. What a lazy way to balance the game and reduce player choice. You throw it up as a great "you can be whatever"! promise, but it just turns in to every party being the same, just different actors playing different roles. It's boring.