I've been thinking a bit, and part of the problem is that Freespace 2 is very much a compendium of the most unimpressive moments of the collosus.
The sixth wonder: It warps in and blows up a deimos. It blows it up quick....but heck, a hatshetup did that in the very first mission.
The mission after that is just a resupply mission, and it doesn't even show up in time to blow the cruiser to kingdom come. Joy.
The next mission we see it is the last of the bomber squadron missions where it annihilates an Orion that tries to crash into it. This would've been more impressive if the two missions before it didn't both involve your puny inexpensive bomber squadron annihilating Orions. And cruisers and corvettes and just about everything else in the universe.
The we don't see it again till high noon, where it caps the Sathanas. Which would've been real real impressive - if it hadn't come directly after bearbaiting, where you (pretty much alone, since your wingmen are useless) turn the said Sathanas into a giant paperweight and then blow up a Demon class destroyer just cause you're alpha one and you can.
Then you get their finest hour, where they sit back and let the cruisers and fighters do the work till they take out one Ravana (and you take out one yourself earlier in the game, so its not too too impressive) then blow up.
They really could've given the big C some more action where it's actually impressing us, y'know?