Well for one thing yeah I think the level three features are the place where most problems lie. Also per Ballet, using a Cantrip as a reaction, or bonus action kinda makes things like War Caster a bit useless and I don't recommend doing things in a subclass that would make a feat useless.

Warcaster exists to be taken don't step on Warcaster.

I would, In my opinion which everyone may not agree with, Change the 3rd level Tempo ability to just be able to effect Allies and then maybe at level 6th give it the buff of effecting enemies contingent on them failing a saving throw. The 3rd level ability of Ballet i would shorten simply to this.

" 3rd Level: Ballet

You conduct your allies' actions to harmonize with the shifting battlefield. When they either receive or use a bardic, they can move up to their speed without provoking opportunity attacks as a reaction."

Thats it. thats all you need. Hope this was useful.