The final part of ARR story doesn't make enough sense.

[Enkidoh]

Details aside, the point is that such a conflict would basically scream to the Garleans "HEY LOOK WE'RE INFIGHTING COME TAKE OVER." Especially with a new emperor, that is an extremely dangerous prospect.

Yeah, and where have we seen this before? *cough* Ala Mhigo *cough cough* The more I think of it, the more I'm certain the Syndicate's rebellion is actually part of a Garlean plot to 'divide and conquer' Eorzea - they know Gridania is too insular to destabilize and Limsa Lominsa being a Thalassocracy simply could weigh anchor and evacuate to calmer waters. But Ul'dah was the most obvious choice to destabilize politically - it's the centre of Eorzean trade as well as having the most weak government, a figurehead monarchy with power vested in a rich plutocracy was never going to last.

And like what happened in Ala Mhigo with the purge of the Fists of Rhalgr (Ala Mhigo's most powerful military force) and the overthrow of the 'King of Ruin' Theoduric after a brief civil war, assassinating the benign yet heir-less and powerless Sultana, framing 'Eorzea's Champion' the Warrior of Light and the Scions of the Seventh Dawn for the crime, and then watching the plutocratic Syndicate tear itself apart through infighting as each member draws a line in the sand and unleashes their private armies against each other - soon the beleaguered Ul'dahn citizens would be begging for the Empire to move in and restore order - befret of the Scions and the Warrior of Light, they would obviously feel that Imperial domination is preferable to complete anarchy.

As Kan-E-Senna said in the original ending scene following Operation Archon, (paraphrased) "If one nation falls, so shall we all." Ul'dah's fall would quickly result in the rest of Eorzea being brought to heel under the Garlean jackboot. It's so obvious as to be pretty much shouted in big flashing letters.

I really hope I'm proven wrong though.