The fact that Protect and Esuna are somehow optional skills by the game's definition really rubs me the wrong way, and more or less just reeks of the developers tossing them into the cross role section because they couldn't think of anything else to put in there for healers.

The other roles don't get role skills that are literally 'have this or enjoy having a high chance to wipe' like Esuna is (although Provoke may count too).