Wing Commander CIC

My query revolves around the confederation's fleet of capital ships in WC1 and WC2. In WC1 there are three basic capital ships-the Tiger's Claw strike carrier, the Exeter destroyer, and the Drayman transport. Now the Claw and the Drayman are pretty well represented in the game. Yet, the Exeter seems to be a fat pig that for all its weaponry seems unable to defend itself. The Diligent and the Venture are one off ships that i only saw once each and i wonder what role they play. In WC2 which i am not totally familiar with there seems to have been an evolution in capship design for Confed. The Waterloo cruiser and the Gilgamesh destroyer exists along with the Concordia dreadnought. Now do they both fulfill similar roles or is the Waterloo a different beast altogether