Okay so after a few runs in the Deltascape as WHM I have another major concern you might want to add to the main post or at least point out, Reiryuu.
Esuna being removed from WHM, and set as a Job Action to share across all 3 healers (along with the removal of Leeches and Exalted Detriment) is not only unfair to White Mages for having one of their key abilities removed, but is also bloody gamebreaking in end-game raid content. I know this is WHM feedback, so bringing up SCH and AST abilities isn't really suited for here, but seeing how this pertains to something that belonged to White Mage I think it's important to bring up.
Imagine being in Deltascape V4.0 with two healers that don't run with Esuna. Now think about the fact that the Doom ailment exists, and that no changes have been made to it so in order to remove it from someone is to Esuna is. But, neither healers have Esuna. And neither are SCH, so they can't rely on a fairie to remove it for them. And there aren't any RDM's or BRD's to use their cooldown removals. The fact that Doom is in pretty much in all of the end-game raiding content, and no changes have been made to it so that it can be removed from full healing or other methods other than Esuna, basically forces all 3 healers to use up an Action slot with Esuna. Because if you don't run with it, you're going to get people killed because this is how this system works now. That is not a good change to gameplay. Instead of encouraging different kits and ability setups all it does is force us to all use the same stuff.
And don't even give me "Well because you've run it now you should know to set Esuna as one of your abilities when going into it." That should not be an excuse for poorly thought out execution of a battle system. Having to go in and swap out Job Actions based on the raid or dungeon you go into should not be something we have to do in order to stay useful and capable of running high end content. It's a tedious and broken system.