BEFORE I say anything I have to declare, that I am NOT part of the modding team, and this is my own PoW with some knowledge about how the team does things... and some hard facts.I can see your point in trying to defend your idea by any means necessary, but accept it. THIS IS NOT GOING TO HAPPEN!
First, as Corey, the mod designer declared not even once, missions are goddamn hard to create. The mission with the Katana fleet took them a month or something similarly ridiculous time to create, and that was a small one.
They also intend to follow the (old) Lucasarts cannon, and therefore GCs like this are not likely to get in (not likely means not a chance). They have far more work with the mod as it is, without giving time to create GCs like this too.
Only two non cannon GC got into the mod. One of them is the From the Ground Up, what's only intention is to give you a heck of a challenge, and the other is Empires at War, which's only purpose was a GC WITHOUT the New Republic, because that is LITERALLY THE ONLY ONE!.
The ThRev. team also gives you the chance to play from multiple sides in every GC. What you suggest is a Remnant only GC, where you can't play as NR, PA or Eoth, therefore every player who doesn't have the IR's play-style will not even play the GC, not to mention the difficulties it would bring by creating a brand new Era system, just to make it work...
Your suggestions would also need to code a few new models into the game, further increasing it's already huge size. If you noticed, the EaW and the FoC folders are roughly 3.49 GB together, while only the mod takes roughly 4,84 GB of memory, so it takes more than the base game. Not even by a small amount and with 2.2 new units shall arrive, also increasing it's tremendous size(compared to base game).
Now that all of this have been told I also have to tell you...
I FREAKIN' LOVE YOUR IDEA! Looks epic and all. It is just not for this place. For a dream, it is all right, but it will only remain as a dream.