Peter Jackson's: King Kong Game, had a great level, it was a swamp, half the level is on Dry land, and the majority is a swampish flooded area almost up to your chin, travelling too far, and a Swamp-Croc-Lizard things (Udusaurs) would appear and attack.http://www.youtube.com/watch?v=RVfQne-DCYI
I would love a map like this, for DLC ofcourse, since the Maps have already been announced for David. If Orion was inhabitated by Creatures, other then dinosaurs, then they would be perfect for Wildlife in the Swamp (I dought much Dinosaurs would stick in a swamp)
It will also be cool if there was no Large functional base, but an abandoned one, covered in Ivy, Doors pryed open, with no lights inside, you could go in there, repair it and at least get the defense grid and lights online. (Hey that could be a Pretty epic survival mode map) And just for Shitz 'n' Giggles, some sort of Camp, with tents and a fire and stuff.
But that's my imagination, dought it would be suitable for ORION series.
(And yes, I do tend to get carried away)