Currently there are only five ships with flight-decks in the game. The Condor, the Gemini, the Heron, the Astral, and the Odyssey. Of those, the Condor and the Gemini are refitted freighters, the Heron is a "fast carrier" which implies the existence of "slow carriers" of similar size, the Astral is exceedingly rare and only sold by Tri-Tach markets, and the Odyssey is similarly exceedingly rare and only sold by Tri-Tach but it's also a battlecruiser with a single flight-deck tacked on the back. We're missing military-spec destroyer-size carriers, military-spec slow carriers in the cruiser size, and something in the capital-size for people who don't join up with Tri-Tach. For the destroyer size, I'm thinking something mid-tech, with two flight decks and slower than the Condor or Gemini. For the cruiser size, something that can be the slow-carrier to the Heron's fast-carrier and as such was developed before the Heron, so low-tech, three flight decks, more armor and weapons, and yes, slow. For the capital size, 4 flight decks maybe 5, maybe 1 large missile slot and 2 mediums? Could be either low-tech or mid-tech.
Destroyer variety isn't very good either. There's the Enforcer, the Medusa, the Hammerhead, the Sunder, and the Buffalo Mark II. The Hammerhead isn't great; it doesn't have high enough armor or flux stats to be very tanky, and doesn't have enough weapon slots to really take advantage of Accelerated Ammo Feeds. It's at least cheap, both in initial cost and in maintenance costs, but it needs a bit of a buff. The Buffalo Mark II is kind of hilariously useless. The Sunder is a good ship; it's a glass cannon, and it does that very well, but it's too fragile to be the backbone of your fleet. That leaves the majority of the player's destroyer numbers to be made up of either Enforcers or Medusas, which are both great ships, but there only being two viable line destroyers isn't great for the game. We don't have a phase cloak equipped destroyer either, and a destroyer along the lines of the Medusa would probably have the perfect mix of firepower and mobility to really take advantage of the phase cloak system. It'd also open up the possibility of Tri-Tachyon fast pickets made entirely of phase cloak equipped ships, which would be quite a scary surprise indeed. I'd suggest giving the Hammerhead a buff, maybe moving the missile slots to the sides and adding small ballistic hard-points in their place as well as increasing its flux stats a tad, and adding another low-tech destroyer and a phase cloak equipped high-tech destroyer.