The Garlean Embassy is promising, I've stated in the past that I was hoping for Kugane to have something along those lines so perhaps it will be used for the sake of diplomacy once Zenos is out of the picture. It's unlikely that Garlemald as a whole is ever going to be wiped out - and the story would be very stale if the Warrior of Light and his allies managed to accomplish such a feat in the first place. It'd also bring chaos to almost every corner of Hydaelyn and result in a lot of innocent lives being lost on all sides. I imagine we'll be introduced to a 'Larsa' type character at some point during 4.0 or the patch series and we'll work alongside them to eliminate the corruption within Garlemald but also bring forth stability and prosperity. Hopefully in such a way as to ensure that we don't get another Aymeric apologising for what his people did for the sake of their continued survival.