PROBLEM: The gravitar fight's challenge is subject to ping and is exponentially less fun the farther you live from the server.
Replace yellow bubble with a Force Choke on 1 target and a DPS check:
Gravitar goes "HAH, You can't handle me!" and chokes a random target in a yellow bubble. She must be dealt a specific amount of damage to to for %s or that player will get insta killed.
Replace large blue bubble with stacks of Gravity.
Gravity makes people slower and gravitate towards one another, the more stacks you have the stronger it is. It also disables travel powers at 5 stacks.
Blocking makes Gravity expire over time. Not blocking stacks Gravity.
This makes her cascades more lethal, and give her an ability that detonates Gravity at 5 stacks and insta kills the player.