Let me ask quick question what just popped into my mind.
Will this mean that the Hunt for Zsinj will be playable from 3 sides from now on?
No, Hunt for Zsinj is still Zsinj and the "alliance" situation with the NR of Rogriss and Solo.
To differentiate Imperial Splinter factions that all use the Galactic Empire symbol, recolor or stylize the vanilla Imperial symbol by recoloring the blue background to red/brown/pink/green/orange
I'd like to be able to give them their own unique identifiers, but unfortunately the game doesn't care if you do that, the only places that really use it are the pips on the skirmish menu (which they won't be available in) and the pips on the HUD in GC mode, which the game doesn't load beyond the fourth one. They default to the Hutt one (which is, in the mod, now the icon slot taken up by the PA). They also use the hyperlane colours of previous factions regardless of their own colour which is slightly more annoying. Also as a side note, factions that aren't the original three can't use any story scripting which is what makes most new game mechanics work (as was mentioned previously, which is why I suggest reading past posts; saves me time explaining things).
Despite how they act similarly to a warlord faction, the Restored Empire isn't one. They were hardliners who wanted to disrupt a peace treaty ending the GCW between the IR and NR. if you are saying they wont be added because it isn't planned yet, fine. However I don't understand why you wouldn't want them to be added if that's what you're saying. They have a great story surrounding them, and it would be interested if there was a mod that manipulated game mechanics so the IR and NR can't attack each other, but they can only fight the RE. Either that or put the RE between the NR and IR and make them fight the RE to get to each other.
I don't want to add them because gameplay wise and in the broader narrative of the era, they're irrelevant. Hardcoded limits aside, they would never be under any serious consideration. They controlled basically one planet (and not even an important planet). If you compare that to even the weakest of the factions in the game as it is, the Hapans controlled 63 and the Duskhan League at least 13. In any GC not specifically focused on them (where we artifically zoom in and expand their territory) this tends to translate to three planets for the Hapans and one for the Duskhan League. And that's
still probably proportionally too high. I'm perfectly fine with factions having a starting point imbalance between factions since this is a narrative sandbox game as opposed to a competitive multiplayer game, but (to give it a Total War-eque, or since you mentioned it in your other thread, Supremacy 1914 frame of reference) if the Hapans or Maldrood are like making Belgium (Luxembourg for the Yevetha) present or playable in a game about World War I/II, the Restored Empire (or Reborn Empire) are like putting
Andorra there. Only, proportionally even smaller.
If we were to make a list of all the factions and groups in the galaxy during this period by size, relevance to the galactic political landscape and capability to expand, it's something like this:
1. New Republic (ca. 19 ABY)
2. Imperial Remnant (Moff Council/Palpatine/Isard version)
3. Empire of the Hand (ca. 19 ABY)
4. Pentastar Alignment
5. Warlord Zsinj
6. Greater Maldrood (Federated Teradoc Union)
7. Eriadu Authority
8. Zero Command
9. Hapes Consortium
10. Ssi-Ruuvi Imperium / Duskhan League
12. Hutt Cartels
13. Corporate Sector Authority
14. Prentioch's Dominion /Sarne / Oplovis / Antemeridian / Ciutric / Grunger
20. Bakuran Defense Fleet / Empire Reborn / Restored Empire
23. Second Imperium
If they cared at all to be involved in this period, the Vong Empire probably jumps to first place militarily considering the GFFA had to form to beat them, and the Chiss Ascendancy would be somewhere around Eriaud Authority (the 14-19 range should probably include more random Warlords-of-the-week as well, but meh).
IF you want to take it from the perspective of what a group provides as far as unique playstyles, rosters or game mechanics (leaving aside what's actually possible in EaW):
1. Vong Empire
2. Ssi-Ruuvi
3. New Republic
4. Empire of the Hand
5. Imperial Remnant
6. Hapans
7. Hutts
8. Pentastar Alignment
Literally everyone else is to some extent a clone/mix of the Remnant and PA with perhaps one or two unique units.
So, if we're going to include a group, they have to either represent a significant chunk of the galaxy or have something really unique about them. Their story is pretty irrelevant considering that doesn't come into play . So, having a group that controls only one planet
canonically, forget what they'd have when reduced to the planet resolution (for lack of a better term) the game is able to represent is pretty pointless unless they have something else significant to offer. Their backstory isn't terribly relevant since none of it is something that can be represented in an RTS like EaW, and the one thing they did do (the attack on Orinda) failed. As for your idea that you put the RE between the NR and IR and they can't fight each other, that's again just one planet they have to get through (so it's a GC with one chokepoint, through a faction with outdated technology) and again is kind of like having a scenario in a real-world game where Spain and France are at war but can only get to each other through Andorra.