i could've seen that happening if the blow hadn't been softened by the Anbu, but after plowing through two Anbu, just like you said most of the force in the attack was gone. When it hit Kabuto it wasn't devastating, and similarly wouldn't have thrown her off by much.
The time taken for her to stabilize her footing from the, now normal, drop kick is probably about equal to the time it took Kabuto to stabilize his own from the stagger, so he wouldn't be attacking while she was off balance or something.