I think hes sexist. Or rather just lack the experience with women.
he's admitted at being bad at drawing them in the past. I don't think he's sexist, not actively anyway because you can see the strange man TRY to upgrade his females but in all the wrong ways. Hinata's upgrade in this war was talking to her crush and holding his hand, she is still ENTIRELY dependent on a male as a character but you can see that he TRIED.
Tsunade was leading the 5 Kage against the strongest ninja in the world who they stood no chance against. She fought bravely, was undermined for being a woman but was the one who dealt the most damage to him. She was totally awesome but totally failed. He TRIED.
Sakura doesn't have development in terms of strength or character and more random bursts Kishi will give us at random times to remind us all that she's still here. Like when she used the Yin Seal out of nowhere, a forced moment of development and one that didn't even make her all that strong. She's still very evidently trailing behind them (literally) and the only person she surpassed was....Shizune? But still, Kishi's trying through all this. He clearly just doesn't understand how to use female characters or how to make them human.
Do you remember the last time two females of the K11 spoke to each other about something that wasn't about a man?