People absolutely do get promoted for simplicity. I've also seen promos rejected for over-engineering concerns as well. I get that the opposite can happen, and at the end of the day there is some subjectivity, and a good deal of optics involved in the promotion process at any large company, but don't be demoralized by this! The minute you give up your engineering judgment and ethical principles in pursuit of some perceived political path to promotion, you immediately lose credibility with the most competent people that you most would want to work with and learn from. I assure you they are sprinkled throughout all kinds of organizations at all levels, so don't let the bozos define your worldview.