Captain K: The WW movie was in a weird spot due to all of the feminist expectations around it. I think a plot point like the one you suggest would work fine in most movies, but it was unusually important that WW needed to basically solo the fight, and win. Moral support or solving other problems are fine, but if there was even a hint that WW only won thanks to a guy's assistance, or if she didn't "Really" win, people would complain it undercuts the side message of feminine empowerment, and not without reason. I think that once there's enough female-led action movies that are also good, they can relax this, but for this particular movie, WW having outside support would have been problematic. Incidentally, if I'd been in charge, I'd have been on the side of write it to be not-really-win. Ares would just refuse to fight her and say he's more of a politician / businessman these days, not a direct warrior, and all these humans are much better at war and peace than I ever was, good luck corralling them. It'd get across the point that some battles aren't won on the battlefield.
