...and no more after that. I'm not counting lockbox ships though with this. I also don't count small craft, since those are mostly used in only a few things. Anyways, here's why:
Feds have ships that can do any role. They have 'pure' ships that basically serve one function and no other (like the Defiant, which does lots of pew pew, and little else). Then they have more hybrid ships as well. Generally I consider this at least a vessel of one type, with a Lt. Cmdr slot of a different class on it. Along with that, they also have the 'versatile' classes, which have a Cdmr of one class, but have a Lt. Cmdr and Ensign universal.
Pure Fed escort: Defiant-R
Engineering Fed Escort: Armitage
Science Fed Escort: Multi-Vector
Versatile Fed Escort: Chimera (1000 Day vets and lifers only, but it counts I feel)
Pure Fed sci ship: Voyager-R
Tactical Fed sci ship: Fleet Science Vessel Retrofit (only one I found)
Engineering Fed sci ship: Nebula-R and D'kyr
Versatile Fed sci ship: Vesta variants (to be released soon)
So...with one exception, the Fed side has a ship for virtually any role now, regardless of anything else. And I am not including lockbox ships, and only one Fleet ship.
As for not including the Odyssey, despite it's more science-leaning capabilities, I didn't do that because it IS universal slots, you don't have to slot engineering, but you don't have to slot sci or tac if you don't want to. There is no Fed cruiser with a Lt. Cmdr Sci.
My point from all this, is once the Fed side does have a cruiser with a Lt. Cmdr science slot, they won't need anymore ships.
Now I doubt I'll be changing anything, just bringing up a point of just how many ships the Fed side does have, and they really have few 'niche' roles left to fill. The only thing they don't have is a pure Universal ship, and I hope that never happens.