Well, it's not like Lynda Carter went all ripped for the WW role herself.
Yeah, but Lynda Carter was not really any more credible as Wonder Woman than was Adam West as Batman.
Which was the point. The first season of WW on TV was meant to be just as big a superhero spoof as Batman, which meant they didn't need somebody that actually looked like a wonder woman. They just needed somebody brunette and pretty with reasonable enough command of english that she could memorize her lines.
Which is the same mentatlity they seem to be using for the new film.