Welcome to the forum Tia2, I do agree with you. it would be nice to make the avatars more personal. but the different frames and sizes of the avatars would be very hard to program into the poses. there would be lots variables to consider when having that kind of customization.
Unless you don't mind a auto change to default size when moving to a pose. but Don't feel discouraged, we of forum would love to hear more Ideas you have.
The more the merrier.