Miranda was a genetically engineered human to be in peak physical and mental condition, as she points out multiple times. She's one of the companions you can fuck, struts around on high heels, wears a skintight suit showing plenty of cleavage and wears a damned collar. On top of that, they slapped the face of an extremely attractive woman on top of it.
If you don't think she's about sex appeal, you're living on a different planet.
edit: Iirc even during her romance, she talks about how she wants Shepard to admire her body or some stupid similar stuff.
additional edit :
from the mass effect 2 art book : https://i.imgur.com/fHYylK1.jpg
from the mass effect 'universe' art book : https://i.imgur.com/Mph7un5.jpg