SFT variants are fun and plausible but you also have to think about their potential use in a strategic sense. The Lyrans certainly have the technology to build their CVA; they chose not to do so because it didn't fit their philosophy.

I have no problem with the SFT variants as a concept, but the Gorn and Federation are simply too powerful. I can see the Kzinti mounting Disrs on the engines and filling the space with non-combat systems because their neighbors do, and the Hydrans didn't improve the combat value by moving the heavies to the engines. In fact, I like the Hydrans enough to allow them in a campaign if the player wanted them. Just my $0.02.

You know...in F&E I have built that Lyran CVA...once. I built one on a turn when I was cash rich, the Kzintis were reduced to the Barony and the Expedition was trying to attrit the Feds down. The Feds were making me pay ridiculous repair bills because I didn't have any carriers to suck up a round or two of losses. But I was reacting to a set of uni-que circumstances. The Kzinti capital going down is not always a certain thing. The point that I was trying to make is that each race only has so many conversions that can do in any given length of time. For nothing but variants to be running around is wholly impossible, uneconomical and tactically and strategically unsound.

The Klingons can produce 18 D5 hulls per year. The D5 is a superbly convertible ship. How many of those end up as something other than a vanilla D5? Two? Three at most? Say a D5V, D5S and D5M per year? Maybe the occasional AD5 depending on how many big carriers you've got hanging around or a D5D if you're cash rich to do some drone bombardment. There just isn't the money, conversion facilities or need to do anything else. The Klingons are always short of command ships. How many D7's end up as D7Cs? Every variant you make takes the ship out of battle for six months to a year and clogs up the construction/conversion facilities. Lots of variants are nice. Some are actually quite useful and some are outright essential. But few are ever going to get built.