Well, I don't want to add too many ships, nor do I have the time to do that. Sometimes I just leave them for next major release. (I know, that's just another excuse for my lazyness.
)
There're also many people requesting Dominion and Cardassians. I would like to add them as well, but I don't want to change the playable 4 races, and I cannot make a working multi-race map yet. So the plan is still in a WIP stage. The ships are ready, specs are set, but the map I made just crash the game.
On the other hand, I can play DS9:DW on my laptop and it's working fine. When you have that game working, it's the best ST game featuring the Dominion War. So somehow I lack the motive to make a mod with Dominion and Cardassians...