I think the idea isn't that you want to allow 'necessary sacrifices' but that they maybe inevitable and in trying to avoid them you can risk failing in your goal. Using the Dragonsong war, Nidhogg is a necessary sacrifice. We have little option but to kill him. Its like saying, 'In trying to save everyone you can end up saving no one' or 'understand to achieve your goals you might need to pay a price'. Peace can only exist in Ishgard with victory in the Dragonsong war because Nidhogg isn't willing under any circumstances to consider peace as an option.

Also the English version doesn't really give much of a sense of it but some of those other localisations make it sound like this might be Hydaelyn's last message to us, at least for a long time. The German one almost sounded like she is begging. Very ominous. I wonder if we will see Hydaelyn bow out as a player in this patch. That would be huge.