I disagree on item #1 (Taste). A good designer should solve problems, not do something that looks beautiful to you.
I don't think taste conflicts with problem solving skills. They can coexist - because design is choosing which solution to apply to a problem, and the choice reflects your taste / stylist preference. Rarely is there only one answer to a problem. Agreement in taste is important else it will be hard for you and your designer to move any design decision forward to implementation.