Mako class Corvette (200,000 tons) {LCAF}
Robinson class Transport (500,000 tons) {AFFS}
Davion II class Destroyer (580,000 tons) {AFFS}
Commonwealth II class Light Cruiser (700,000 tons) {LCAF}
Congress class Frigate (760,000 tons) {AFFS}
Tharkad class Battlecruiser (900,000 tons) {LCAF}
New Syrtis class Carrier (920,000 tons) {AFFS}
Durendal class Destroyer (? tons) [Galax?, drawing board]
Avalon class Cruiser (770,000 tons) Kathil
Covenant class Cruiser (790,000 tons) New Syrtis
Mjolnir class Battlecruiser (1,250,000 tons) Alarion
I love some of the original FC historical ships and wouldn't mind seeing some of then reborn but none of that seemed to be on the drawing board in canon.
That said, when I look at what exists already, much of that is covered.
The Fox clearly replaces the Robinson in role.
The Commonwealth/Congress & even Covenant are all mostly covered by the Avalon.
The Mjolnir can overpower the Tharkad & New Syrtis.
We don't have a "Fast Corvette" as you mentioned but the raw speed of the Avalon & Mjolnir means the fleet is anything but slow.
So what are we missing, lack, in terms of the original &/or need to expand on.
1. Well, a Destroyer sized ship obviously.
2. Internal Cargo (Made up for by added the large # of Colars)
3. The Fighters of the New Syrtis (Slightly made up for by colars as well.)
When it comes to the Durendal, as I've mentioned before, I've built it as a Davion-II type vessel, but also built it as a War-Monolith type ship too w/ like 8 colars.
Either option is possible given what the FS has shows us historically.
Adding a bit of "York/Riga" to it would also help out in the lack of NewSyrtis/Carrier abilities.
I think the biggest thing the FC navy needs is a "Block-II" with minor "tweaks" to the existing 3 ships.
You don't need to build them from the ground up again, the SI could be lower but for simplicity, I'd probably not touch engines, SI, or colars.
Instead, the Weapons, Armor, Smallcraft could all be tweaked to pay for some deeper Cargo & adding LFBs to the Mjolnir.
Optimizing the guns for Bracket & Anti-Fighter solutions & consolidating the Standard Scale weapons, & adding defensive Screens/AMS would all be fairly minor tweaks.
Launching a "York-onolith" type Destroyer/Carrier & ramping up all shipyard to just grow the #s would be nice.
The LA managed 2 Mjolnir (1.5 really) in the time the FWL kicked out 7? of their SuperCarriers.
That doesn't seem right to me.
Now obviously a lot of that had to do w/ the split & boot strapping the program historically, but a united FC that still ended up with the Mjolnir (BC) wouldn't have those issues.
Ideally you see the shipyards expanded to something like this...
Galax = Fox-II + Durendal
Kathil = Fox-II + Avalon-II
New Syrtis = Fox-II + Mjolnir-II
Alarion = Fox-II + Avalon-II + Mjolnir-II
With Fox production being the most wide spread but also limited to say 1 slip/yard at each location while remaining are for the larger ships.