The above concept has a version of such an ultimate, but I'll excerpt it here:
Freesia spins and, after a short wind-up (0.5 seconds), deals 150/225/300 (+0.4 AP) magic damage to all nearby enemies (400 range) and removes all Spirit Samba marks from all units in the AOE. Freesia also gains a shield that absorbs up to 60/70/80 (+0.2 AP) damage for each enemy Champion hit, and lasts up to 6 seconds.
>_Maximum shield strength: 300/350/400 (+1.0 AP)_
>If Freesia last used Spirit Samba on an allied unit, Grand Finale will knock back all enemies struck. If Freesia last used Spirit Samba on an enemy unit, Grand Finale will vacuum in all enemies struck.
The idea of this is that Freesia is constantly darting between allied and enemy Champions, and using this she can select between either a pushback or a vacuum with her ultimate (but not both at the same time). This can lead to some awesome plays, or terrible terrible mistakes, separating "good from great" players.
But would such an ultimate be too packed?