I can imagine that there will be different body type options once the game is released, and that they are not yet included because it is not that easy to implement them.
As far as I know, you can not simply use the same rig for all body types when you want your characters to look/move realistically. And the animation of more pronounced muscles should also be realistic.
There is also a lot of physical interaction between our character and the companions/other NPCs. I think it is (currently) simply more easy to consider only a few different character models for these animations. There already is a character with a more muscular body type, Halsin, but our characters do not really interact with him physically.
I would really like some variety in body types once the game is released, but to me, it is perfectly fine when it is not yet implemented in early access due to time constraints.
