So ive always felt the plan they had for reviving all of their civilization was not really thought out. We ARE the souls of the Amaurotines, fragments of them as theyve very plainly told us. If you feed our aether to Zodiark what exactly are you bringing back? You think hes just going to give up all the power he gains from souls and release them back? The sacrificed life forces originally are what allowed him to even take form and Emet wants ALL of them back. Now Emet admits that all the ascians were tempered if you talk to him in the Solar after one of the cutscenes so im not sure if this has some bearing on his ability to think of these angles because Zodiark would want resurrection and wouldnt want that kind of questioning.