I don't know exactly, but it feels like there was something about the scene where Usagi gets back from the fight with Pharoah 90. She comes back bearing the infant form of Hotaru. It's a scene that could have looked like a Madonna and child, except that it didn't. Instead, her clothes are tattered, and her eyes look dead, defeated. We don't get to see exactly what she did, but Usagi obviously lost something important that day. I mean, if she hadn't, does the next episode even make dramatic sense? If she had come out of the other dimension, gave a smile and a V-sign for saving everyone, there wouldn't be anything left to prove, you know?
So I feel like the outers were proven wrong about the "win at any cost" philosophy, but on the other hand, they were proven right about the "military victory against true evil always requires sacrifice" part. (And even more so, if you continue on to the Stars manga.) Haruka and Michiru were too eager to sacrifice, but when it came to the end, Usagi literally had to wear her soul on her sleeves to win.
So I feel like the outers were proven wrong about the "win at any cost" philosophy, but on the other hand, they were proven right about the "military victory against true evil always requires sacrifice" part. (And even more so, if you continue on to the Stars manga.) Haruka and Michiru were too eager to sacrifice, but when it came to the end, Usagi literally had to wear her soul on her sleeves to win.
"Kitto daijoubu da yo." - Sakura Kinomoto