Again, it's not the same and you're making a false equivalency. Garlemald was destroying lives and cultures on a global scale for no reason. Before now, Eorzea was a backwater fighting regional conflicts between multiple people groups with swords and arrows for 1500 years. Garlemald has been bombing cities from the sky for 60 years to get revenge for something that happened 600 years ago and then expanded beyond that to destroy countries that had nothing to do with them at all.
The treaty was broken with the Kobolds, not the Sahagin. The Sahagin have been enemies since before 1.0, they and their Serpent Reaver allies have been pillaging for years and burned down the village the fishing guild lalafell woman came from.
Going to need a source on this last bit because I don't remember that.
In any case, the recent Saints' Wake event had a Gridanian Elezen married to a Moon Keeper Miqo'te. In a world where inter-racial marriages are frowned upon, let alone one between a Wildwood and a Moon Keeper, that's a big deal. But the likely case is that the writers don't care about that plot thread anymore and we won't see racial tensions as much going forward anyway.
My point in my previous post when I brought up the Eorzean nations is that they had full-on arcs where they're shown to be really crappy, try to be better and end up slipping, but then overcome their issues and resolve their problems or at least get on the way towards doing so. It took a decade of this to get to where we are now. During all that time, Garlemald has been shown on screen and painted as the "well we may suck, but they're worse" crew. It would be extremely cheap to the majority of the playerbase who have been around since the very beginning, are deeply engaged with the story, and aren't edgy imperial fans to have Garlemald just say "oops, sorry", put another Galvus on the throne, and keep the empire around.
If it was well-written, sure I'd still play it, but it would be a disappointment in that there's so much else to do for a whole expansion and I'd rather the game do something new with the close of the previous story instead of going back to the previous story again to give us more Garlean drama as if we haven't had enough. I'd support a side story where we help them since there's a lot left over to be done and I want to know more about the empire, but I don't see us getting anything more than a side-story arc devoted to it, if that, let alone a whole expansion about rebuilding.
The empire is gone. Provinces are in open rebellion and the military can't do anything about it. The 1st, 2nd, 3rd, and 10th legions have surrendered in EW and the 10th was supposed to be the last hope for Garlemald so who knows what the state of the others is like. The threat of the military was the only thing that kept the whole engine running and now that's gone and the capital has been destroyed, it's only a matter of time before the rest collapses like dominoes.
Considering that not even Landis was considered a suitable location for the Garlean refugees in the role capstone quest, there's probably no place for them to go and the provinces are lost. The royal family has been wiped out and they've already been stated to be moving on away from that with Fourchenault going to find the surviving senators. The capital is under occupation and while they're still letting them decide their own fate and path forward, the matter of defense is currently handled by the occupation, which isn't exactly a strong point to maintain an empire from.
From a gameplay perspective, we already have a Garlemald zone and it's a wasteland filled with monsters and ruins as well as an occupying force that are all tied into the local sidequests so Garlemald won't end up being completely fixed ever anyway.
Another thing to remember is that the game is written by people who are pulling from their own cultural experiences. Japan was fully occupied for 7 years and its empire was dismantled and the parts returned to the original owners. The same will probably happen to Garlemald and the writers could be drawing from that time period.