That's the kind of reply I was hoping for. XD
And all of that sounds awesome. I would add one idea for your consideration. If you have ever played the game Gigantic. It's a Moba and the goal (like most Mobas) is to kill/destroy the enemy guardian. What happens is the players score points by completing objectives and getting kills. Once the "bar" is filled the attacking team's guardian rushes the enemy guardian, pins him down, and the players must attack the enemy guardian.
If you were to do this, what you could do is have the mothership(when score/goal is reached) fly in, destroying everything in its path(AI and Turrets), and disabling the enemy mothership for your team to attack it. They would have to both deal damage to the enemy mothership while also avoiding being killed by enemy players.
Just an additional thought.