Agreed, with the exception of the Thrakhra-class -- I thought it looked more Kilrathi than most 'game' Kilrathi capital ships.
I'm fairly ambivalent towards the Ralari. It looks much more impressive in the game, but the movie design sort of suits the 'strategic bomber' description of its use in the Confed Handbook. I'm a sucker for that potential use -- I've always felt that Wing Commander really needs a 'strategic bomber' analogue.
The turrets and such on the Broadsword and its kin eare clearly based on the B-17... but a more direct version would be cool. A big multi-engine bomber, too large to take off from a carrier... so you have these huge formations of planet-based space-bombers that cross the line to bomb enemy colonies, and you have to fly escort missions for them.
The Fralthi, Sivar and Snakeir were all very generic. They might have been cool if we'd seen them in a big broadside-style battle where the cannons on their hulls were used, but mostly they just sat around, looked similar to eachother and took damage.