You two are no less picking and choosing your own favored narrative. Do remember that the first time Luna was presented, she was a sitting pretty girl, and it wasn't until backlash that we suddenly have unrealistic gun-pushing scene (as if all the soldiers would lower all their guns just because she pushed one out of her face!) and Leviathan.
Oh, it's so great for a female character to be so determined to help the main male character, you know, other than perhaps standing up against Leviathan for reasons unrelated to super special Noctis.
In the context of the scene, the focus is on Ardyn, without you seeing Luna's face. What that means is Luna took a slap to serve to make Ardyn look more evil. What year is it, that writing scenes with female characters as props to characterize male characters could be excused?
You say that female characters that go around kicking butt are not unique, but name one heroine that doesn't have a shitty male-oriented visual design and isn't plagued by some obligatory romantic subplot? The west is making progress on this front, with their Mirror's Edges and Horizon Zero Dawns. When we ask for better female characters, we are not merely asking for physicality, we are asking for a female character that isn't just a tool being pushed around by all the other male characters. Luna by all means does not fit the bill nor can you excuse that by saying "check out this one scene with Leviathan". As a male you can be satisfied by a crappy little bit of lip service; as a female I am no longer going to tolerate it.