My own thoughts on this are very simple: It's called acting for a reason. I cannot understand why people whip themselves up into a frenzy over things like this. As long as disbelief is suspended I really couldn't give an airborne fornication about the ethnicity police. That goes doubly when, as you rightly point out in in this article, the ethnicity is in question in any case. Gal Gadot will do a great job, assuming she is working from a great screenplay.