Right now, the Fleet mission in which the player escorts an Aurochs supply ship completes itself. Only one or two small groups of enemies spawn, and they're easily repelled by the Aurochs's TeV9. Even if they weren't, their weaponry wouldn't be sufficient to pose a major threat.

For the Ares variants of the attackers, upping the number of attackers spawned and adding a Chasm or two into the mix should fix the difficulty. For the Rogue Fleet, something creative would need to be done, as they don't currently have any weapon that can reliably damage a ship with internals.