The current state of Frontline reminds me very much of how it was before 4.5, when there wasn't any damage modifiers and people only went with healers and ranged. There are damage modifiers in place now (Melee DPS and Tanks take 40% less damage, everything else = 20% less) but I don't think that it's enough. Jobs are currently balanced with expectation that you have no duplicate jobs in the same party. That limitation isn't place for FL and RW.

I think they need to add modifiers to LB generation for every job. Some jobs, like SMN, BLM and WHM need to have slower LB generation so they are less broken while others, PLD and SGE need to have faster LB generation to be more viable.

The immunity from Purify need to have its duration increased in FL and RW. Make it 8 seconds while also making you immune to knockback and draw-in actions.