(ShB Spoilers) Didn't Hydaelyn, uh...

[Kokomi]

I honestly want to side with the Ascians (minus the genocide part) but it's tough without more info.

The vast majority of the Spoken races present in the world of Final Fantasy XIV are sundered Ascian souls. Only the lesser races would perish in resurrecting the Ascians within Zodiark.

I don't think this is true - most people possess mortal souls that dissipate into the lifestream once they die (level 50 MSQ quest "What Little Gods are Made Of").

Near as anyone can tell (and as hinted by official sources) the Ascians still have their own free will. Whatever Zodiark tempering them did, robbing them of the ability to make their own decisions apparently was not part of it.

We don't know that Zodiark didn't do other things to tempered Ascians other than making them mindless slaves. Maybe they became unable to do anything that would harm their god and they end up rationalizing this to themselves.

It stands to reason that life as a whole would be better for everyone if the rejoining were allowed to proceed unimpeded.

If we take what Emet said at face value, then yes. Still, this doesn't mean that being shattered is all that bad. There's also that pesky problem of creation magic - if we were to rejoin and stand on equal footing to the Ascians, then we might be in danger of causing another calamity in the same way as the first one.

The Spoken races exist on all Shards, and that means that they were around prior to the Sundering. The New Life the Council hoped to sacrifice included these intelligent races - but being mortal and ephemeral as they were, the Council saw them as lesser life forms (I mean, the wretched things all die in a century or so anyway - what kind of existence is that?), and thus not worthy of consideration.

Good point. I guess instead of just making plants and animals, Zodiark also created new intelligent, but mortal, life. Now we're talking about ending a mortal life to bring back an immortal one (assuming this was possible). Seriously, that is one explosive moral dilemma, although tempering complicates things. The more I think about it, the more I hate how this was brought up in ShB because it's one of those thought experiments that will never happen in the real world but still makes you feel horrible about weighing the value of life.