Deathflare among most, and if you have 2 SMNs, the game's pretty much done unless you have a Monk since there aren't any REAL gapclosers other than Plunge by a DRK or Holmgang. Even then, the opening burst from SMN will pretty much wreck anything since there isn't a single Magic Defense increase unless you have WHM(25% Focalization), which even then doesn't matter since the damage is so high.
Honestly I'd prefer to see Deathflare be more of a 25% HP AoE instead of like 75% then get stunned by Tank/DPS momentarily and burned by DPS. Paired with a DEF Buff, unless you have One Ilm, then the game might as well be over unless you're good enough to kill the SMN in time. Might as well be a Summoner War.
