Make a small change that would break a class completely.

[Ophie-Mio]

WHM in FFXI had a spell called Reraise that allowed you to do exactly that.

(1.0 XIV also had a Raise 3 that allowed you to raise a person with no weakness.)

This isn't true. Reraise I/II/III would automatically raise you once K.O'd but you still incurred all the negative effects of dying. Dying in FFXI meant that you would raise weakened and would lose a lot of xp from your current pool of xp. At most, you would delevel.
So, Reraise III (the best one) would restore 90% of lost Experience Points and 50% of max (Weakened) HP.
So yeah...reraises were nice but they weren't so OP.

My contribution! WHM's LB3 raises everyone with full HP/MP, unweakened and buffed with Protect/Stoneskin!