But didn't Satsuki say the kamui designs were a mark of brilliance. Unless she was only referring to Senketsu. It seemed like she was referring to Kamui in general. At the same time, it makes sense that Juunketsu would be made to cover the user but I'm not sure how Satsuki would force it to take a revealing appearance sinse her ability to synchronize has been "sham" really.
She wore Junketsu by sheer force of will, and turning it into a revealing outfit was probably one of the few ways she could control it well for as long as she did. She probably took cues from watching Ryuko when she thought of that idea and knew how to make the best of it from what she learned from her father. He probably thought her a lot about how to make use of the Kamui without the need for a "wedding".
But who knows for sure. Lets not forget that it seems a lot of time trigger has been making things up as they go so there were bound to be inconsistencies in the story.