Awfully weak story... or is it? [WARNING:SPOILERS]

[Kayokane]

No, she's just threatening the homes, culture, and livelihoods of the beast tribes (particularly the kobolds), breaking a long-standing peace treaty because territorial expansion is super awesome fun times. But no one cares when it's beast tribes, huh?

ignoring the fact that Limsa Lominsa broke the treaty with the Kobolds several generations before Merlwyb, the kobolds did not instantly respond and remained relatively passive until they were able to summon Titan after the Battle of Silvertear Skies, when Midgardsormr was felled taking down the imperial's flagship, Agrius.
or at least that was my understanding from the LL city part of the main story

[Naunet]

the kobolds did not instantly respond and remained relatively passive until they were able to summon Titan after the Battle of Silvertear Skies

They didn't respond largely because they had no effective means of combating Lominsa's military. It was either give up the land or get slaughtered. So yea, when they finally had the means to fight back, fight back they did.

[Kallera]

They didn't respond largely because they had no effective means of combating Lominsa's military. It was either give up the land or get slaughtered. So yea, when they finally had the means to fight back, fight back they did.

The governance of countries is not like a game of Civ5, where there's enough for everyone and trustworthiness abounds. My point is, the 3 city states are looking to their own affairs because the carnage wrought has left them in a weakened state with enemies at the door. So no, no one cares about the beast tribes. Not since the little moon dropped and the legions who dropped said moon tried to slaughter us. The times are more desperate than you think. It's only when the story is finished that one major threat out of several is done with.