The only issue I have with healing in FFXIV is Esuna.

It cures debuffs in the order they are listed, so if you only really want to get rid of the worst one for that particular class or situation, which is, say, the third one listed, you'd have to cast Esuna at least 3 times before you can get rid of it, and chances are it'd already have had its full effect by then and disappeared on its own.

I'd prefer a system more similar to WoW, where cleanse does cure every Curse and Magic ailment, but has an 8 sec CD.