Impact of selecting your level 30 class change

[Rongway]

I think you're only perceiving such a loss because you're overestimating the value of the various role actions available at Lv30, and this is quite normal. You haven't had time to see and comprehend the magnitude of their effects yet. None of them are really meaningful at that level.

• Cleric Stance will make things die about one cast sooner, if at all.
• Break has no practical uses. Even heavied, you'll still only get one, maybe two spells, off before the enemy closes the distance, and healers should never kite unless a specific mechanic explicitly calls for it. Solo, you should be able to kill any single level-appropriate target before it kills you; and in party, you should run to the tank if anything tries to eat you.
• Protect doesn't change the number of hits it takes an enemy to kill you yet. It won't make a difference until you have significantly higher Defense and M.Defense than you have at 30. Even a tank with syncked gear at that level will only be able to survive one extra hit from having Protect up.
• No status effect lasts long enough or has a significant enough effect to compel the use of Esuna at level 30. Anyone who's not taking unnecessary damage will survive paralysis or stacked poisons, and if they get low, you can Cure or Medica. Of course it's a good idea to use it for certain more potent or longer lasting effects, but up to 30 it's not 100% necessary.
• It's unlikely that you will run low on MP unless you're grossly overhealing, in particular spamming Medica for no reason. Still, Dreaming is the best role action south of 30 because it eliminates any worry about running out of MP while spamming Stone.

Of course, that's not to say that all these actions are useless forever; they just don't make a significant difference at 30. And you'll get one slot back at 32, and another at 40, so you're not without them for very long. By 48 when you get your fifth slot, they start to have meaningful impacts on combat.