I think there will definitely be an aspect of the cost of war but the expansion is clearly themed around liberation. I think at the end of it the actions of the WoL will be presented as the right call. Garlemald is clearly going to be the antagonists. I think the real fallout of this war cost wise will come afterward. I think its very unlikely that the WoL will be painted in a bad light. In the end the WoL is the protagonist and people don't want to feel like they are on the wrong side. That said showing that their is a human cost to their actions is worth while.

To some extent there was a little of this in Heavensward. Realistically there was no neat solution, no peaceful, clean way to end the war. The conflict involved was just too ingrained. Not taking action was more risky and potentially far more damaging than taking action. To some extent I think this will be a factor in Stormblood but in the end I expect the sense that the WoL is making the right call will be there.