Here are some weapon suggestion. Hope that they are helpful.
1) Chain gun (Tesla gun):
If you played Star Wars Battlefront 2 you know that there are lightning guns. Weapon is charged (That makes it a bit different from other weapons). The more fire button is held (up to limit of 1-1.5 seconds) longer will the electricity arc travel, and be able to chain up more times. It will be able to chain on the ball and friendlies, too.
If you played Half Life multiplayer, you know how funny it is to kill an enemy through the wall. This weapon can attack through planets, but the direction is changed by eg. 5-30 degrees. This weapon is also charged. If it is held too long, punishment awaits the abuser (just like in HL).
3)Pull rope – Ability:
This weapon is also stole…inspired by a weapon from another game(s).
Do you remember ninja rope from worms, or rope from Tux Kart. It can be attached to a ship or a planet. More frags =, longer rope and more durable rope. Both ships are pulled. Ball is affected, too.
Btw Because I am an astrophysics freak, I must ask this. Did you try implementing wormholes? Would it be too much gamebreaking or confusing?
PS Sorry for my English.