Well, it does seem to have its moments - honestly I don't mind my current main's limit break being heavily situational; just makes it kinda neat when we do get to use it.
Anyway, the occasions always springs to mind was during a fight with storymode Garuda - yes it's not hardmode but level sync still means a measure of challenge. Anyway after several wipes primarily around the transition where she blows away the stone pillars, we all got frustrated and someone suggested this time around we just try having me (the tank) fire my limit break right before she'd do that huge, unblockable AoE attack (we were averaging about oh.. 3/4's of the pillars intact? Maybe a little less?). Anyway, she hops to the middle, does her little wind-up, I fire the level 2 tank limit break and shield the party.. and lo and behold we come out the other side, our healer patches up the little we took, and we proceed to flatten Garuda with comparative ease thereafter.
So it certainly does have its uses. Same goes for the other limit breaks. Of course the single target damage one will always be the most used since challenging enemies tend to have a thing you want to hit hard at some point, but the others have their moments. I've seen the Healer limit break pull us back from the brink of a wipe where nothing else would have done (admirable healer pulling that off, since the challenge is seeing when it's necessary and being able to react in time), and we just wiped over and over on the Aurum Vale until a black mage joined in and gave us access to Meteor to destroy all those seedlings when things started getting out of control toward the end of the fight with Miser's Mistress.