Yes they are, but
1) There aren't many built women that are actually attractive, try to name at least 10 buff women actors (with the exception of Holly Holm) to consider for main roles and then think of all the background extras which would also need to be extremely built and attractive which is a very, very, very niche market.
2) If all the Amazonians were nothing but armor clad sexy women, Liberal media would fucking explode. Try to picture in your mind a universe where a movie comprised entirely of sexy Amazonians and then think of all the Daily Mail, Huffington Post, Buzzfeed etc, etc, articles would be written titled >"Wonder Woman promotes degradation of Women by sexualising literal Gods"
Ugh it would be Ghostbusters (2016) all over again
3) If the above happened, this film would get fucking hammered by critics and WB doesn't want to take another kicking.
4) The director is a woman.