To choose the shape, the easier path was taken: this one works, so let's safely do the same. That doesn't mean that the choice wasn't analyzed and justified, n

To choose the shape, the easier path was taken: this one works, so let's safely do the same. That doesn't mean that the choice wasn't analyzed and justified, not that aerodynamic testing wasn't done - for examples, picture here - http://buran.ru/htm/history.htm http://buran.ru/htm/history.htm - show the evolution of the overall architecture, where the Shuttle scheme was just one of the considered factors.