The problem with any large ship is that they become really "bulky", they may be Ultraswank with loads of cool stuff, but their brought down by their size. They are easy pickings for small, fast craft, which either has bombs or can disable or disarm it.
In the "Real World" a ship the size and value of the Collosus would have a minimum of 5 wings of escort fighters(two for ventral duty, two for dorsal duty, and one free-ranging wing to provide backup where needed) , and have dozens of larger screening vessels which would contribute more fighters and firepower. The Collossus' battle group should have no less than 20 warships other than the Collossus and at least two of those should be destroyers of some class.
High Noon is somewhat fantastical also, I find it hard to believe that there were no other GTVA assets that could be diverted to help the Collossus kill the Sathanas. Granted she's powerful, but she also represents a massive investment in time and money, not to mention lives.