Something that bothers me most about Living Memory is how many forum goers seem to like to label the Warrior of Light as a hypocrite for turning off Living Memory while quoting Emet Selch. Let's look at the WoL's actions in both instances.
Emet Selch sought to revive the past at the expense of the present and future through the rejoinings. The Warrior of Light fought back to protect the present and future.
Sphene sought to revive the past at the expense of the present and future through Living Memory. The Warrior of Light turned off living memory in order to protect the present and future.
Nothing about the Warrior of Light's actions in Dawntrail is hypocritical as they still pursued the same goal.
I'll be first to admit that I strongly dislike Dawntrail's MSQ, but this part of the WoL's character was in character. Sphene admitted more than once that she can not coexist with the rest of the shard. She needs to commit genocide against not just the source but other shards in order to fuel Living Memory. Sure, we can bring in Cid and this should have been at least able to consult him via linkpearl. But given we're dealing with a material that until just a few days prior in game didn't even exist on the source, it's questionable he would have been able to do anything to help. Stayborough proves that this isn't something that can be sustained. We know there were other areas like it that also disappeared with Endless that will never be seen again. Even if there were souls to fuel Living Memory, the remaining four areas will eventually fall into the same fate as Deadwalk and areas like it.