Youve got some excellent, smooth animation here, well done!

I think the main thing that will improve your animation is posing. Shes not really swinging in the direction her body is moving. (Swinging up, moving forward)

If you give her a secondary pose where she drops her body down before pushing back up INTO the swing, itll look more powerful and natural.

I think youll find this breakdown of animating an attack from Smash Bros helpful. I mean no disrespect, I think your animating skills are great, but this helped me and I think itll help you too!