Tanks could get a duration buff (10/15/8 to 15/20/25) to help them realistically mitigate more than just a single mechanic or raid-wide attack. This also doesn't restrict LB3 to its required uses and makes it harder to botch. Currently, all three of these have gimmicky uses to save people, and not in most high-end content, whereas these buffs factor in the sacrificed damage from a DPS LB. While LB1 could also benefit from a mitigation buff, giving it a better chance to save people on its own, it's already consistent with LB2/3, which work fine enough.

At the very least, Healer LB1/2 should have a healing percentage buff (25/60 to 40/70) and restore MP by the same amount. LB3 should also restore MP to living party members (it's almost better to die and get revived). The regen/barrier ideas for LB1/2 are nice, potentially working differently with different healers. Allowing them to revive party members would help in giving them more use, and likely wouldn't incentivize raid mechanics as you're limited on uses and still have to deal with enrages, but it would still be hard to balance. They wouldn't be as powerful if they revived people with Brink of Death/Weakness, but that could lead to griefing in Alliance Raids.