Cobie Smulders is a household name thanks to her role in 'How I Met Your Mother.' That show went on for many seasons and was known as one of the most highly respected multi-camera sitcoms. Since then she's taken on a superhero role that is not Wonder Woman. She is an extremely important agent in S.H.I.E.L.D. in the Avengers movies. Her character has even fought alongside the Avengers in some of their battles, despite not having powers. Now that's bad ass.
She was up for the role of Wonder Woman which is no surprise. She has a classic Wonder Woman look, although she's not exotic enough to fit in with the Themyscira we saw in the film. I think she would have made a great Wonder Woman, but her connection to the Marvel universe is too strong for DC to want to muddy the waters.