how about a server?
If it's going to be a rotation map then I've got a bright idea for something that could be used for event material.
Have a system of caves underneath the surface, branching off with multiple entries/exits as a rough idea. Perhaps have one of the cave exits be in the form of a 'breach' exiting into the main structure of the clone base- something similar to the antlion hive breach seen in the mines in HL2 episode 2.
Then on, say the far end of the map, a crashed CIS ship like a munificent with an interior would be a nice addition, though I reckon this might be too ambitious
For the main base itself, a ventilation shaft system with an external entry- once more event potential.
And one last thing for the sake of environment, blizzards at random intervals that reduce visibility.