My least fav. ship class would definitely be juggernaught, though. It's horrid! Lack of ship design, and over all shape. (Sathy looks like a cockroach.) The Colossus is an impractical ship design.
I would love to see a VASUDAN juggernaught. The Colossus is primarily terran. Of course. . .maybe the Vasudans are just too busy.
My absolute favorite would have to be. . . .hrm. . .probably. . .nothing. I think that if corvettes had a slightly stronger hull, and a fighterbay, they could easily replace destroyers. Not to mention upping the size by just a tiny bit. If only the Deimos, Sobek, and Moloch could be combined.