Is limit break not a thing?

[Bourne_Endeavor]

Yes. It probably is better just to use caster LB during his add phase. The thing about a melee LB is that it's virtually never USEFUL; all it does is kill the boss very slightly faster, and with shinryu's huge HP, it kills him barely any faster. A healer LB3 though generally is far more useful as it will save a lot of time if used effectively by preventing a wipe, and a caster LB can be used to shorten an add phase. Tank LBs have very specific and rare uses, in which you HAVE to use them to survive. But melee LB can usually be ignored because if you are doing it ok, it's just a bonus of ten seconds in a run.

By the time most people use melee lb, they could just keep on doing what they are doing and the boss ends up dead anyways. It actually gets less useful the higher your dps is, and really only is vital in PvP imo.

When the entire purpose of a fight is reducing the boss' HP to zero, every little bit helps. Do you need LB3? No. But you shouldn't need LB period. Outside prog, people shouldn't be making enough mistakes to warrant healer LB3. And caster LB3 is only useful in add heavy fights. Why is it useful? Because it kills the add faster, you know, sort of like what melee LB3 does.

For Shinryu specifically, you won't have it in normal and it's a complete waste during the add phase in EX. The LB will do more than the trash has HP, thus melee LBing Shinryu is better as skipping Aerial Blast and Dive means you don't have to deal with those mechanics. Caster LB3 is better at the end, but you'll have two regardless.