As a tank (not that I'm there yet but I've been tanking for years since WoW) I don't mind that job. Every class will eventually get shafted in one of the encounters, it's just our turn first.

Even if Shield Bash is off GCD, you're still bound by your animations. And if you've just happened to hit Rage of Halone, say goodbye to half your party because Shield Bash will not come out.

Since Ifrit (story) I've always thought this was gonna be a problem. When people know you can stun Eruption, they will start to get lazy and demand that you do. That may be fine for some other mechanics, but for something as simple as Eruption, I think it's bet to just make Ifrit immune to stuns and force people to move. We have enough DPS who can only tunnel vision on their hotbar and their rotation. What better time to start training them than now?

Or maybe not make it immune, but make it so that each time Eruption is interrupted, Ifrit gains one stack of Enrage that gives him +10% skill speed, lasts for 30 seconds. Parties can choose to stun and heal through +200% skill speed in the end, or choose to avoid Eruption.