We're talking about differentiating classes here, so lets do that.
WAR= Party wide Bloodbath, Berserk, and a 25% max hp increase. Warrior gains 10 second pacification after it wears off, nobody else gets the negative berserk effect.
PLD= The current Tank limit break
WHM= The current healer limit break
SCH= Everyone in the party gains a shield equal to their max health
NIN= Slightly lower damage than the current DPS LB, but PACIFIES ANY TARGET INCLUDING BOSSES.
BRD= Fills up the parties tp and mp, makes all of their skills free for the next 5 seconds, Halves all cooldowns.
DRG= Current DPS limit break
MNK= a DoT that ticks continually based on the damage the party inflicts while it is applied.
BLM= Current Magic damage LB
SMN= A big disgusting explosive DoT effect that hurts like mad, and when an enemy dies it explodes again, reapplying the DoT to things around it.
Ideas?