I can certainly understand what the OP is saying. It's easy to say "just learn by doing it!" or "trial and error!" but when you're running content that's more than a couple hours old there's often an immediate expectation that everyone already knows everything and sometimes there isn't room for "trial and error." Even in the most hardcore content if it's more than a week old there are many people who just don't accept trial and error. Idiots are going to idiot, but Square could do more to ease the learning process.

That said, I'm not really sure a pop up or tool tip is the right way to handle it. Ideally I would like to see a more active tutorial system like an expansion of the Hall of the Novice. They don't need to go over every single mechanic in the game but, as many mechanics are reused throughout the game, they could easily cover the common indicators and markers so that even if you were going into a fight blind you'd have some idea of what's happening before it kills you.