Why does Sage punish you for using your healing spells?

[Komarimono]

I've found Sage easier to heal and DPS then my SCH. Ya get to toss out very quick shields, faster then any other healer ever could, while doing 3 forms of AoE damage for wall to wall pulling, and can keep the tank topped off with mostly just Kardia when it comes to bosses, tossing out a Dru or Ixo as needed to keep MP up while keeping Kera on cooldown. But gotta remember, there was a stat squish, and some lower level dungeons in roullette the tanks want to chain pull but not use CD's, then ya can cheat and just spam Eukrasia into Dia and easy peasy, not many healer can spam heal like that with a buffer, while moving...

Let us not forget, Soteria(Makes Kardia heal more)+Physis or Krasis? Ya.. Tanks not gonna take much damage as your doing AoE damage, not that I've seen at least.