Making a new frame changes animation, and then you'd also need to do work getting all the different armour types to work right with the new body, I could imagine being a lot of work, specially when you can't forget the team is already having to make animations work for the different body types of humans/ elfs and dwarves, both male and female, already being done in the game. It seems to be really expensive, there was a reddit thread recently from Heaven Con, with some of the DA devs, and they talked about the expense of romances, and the most expensive ones, were the ones that required animations for both male and female, as well as the different races (I think they were talking a million dollars for one like that, which sounded like they were refering to Iron Bull). Anything with changing the animation does seem to increase cost alot.