1. Most crucially: Of all the dps classes, SMNs are the most punished if they accidentally mess up Aetherflow or die.
  • Bane is ineffective (no adds/adds too far away to Bane)? No DWT/60sec dps punishment.
  • Fester, but no DoTs on the target (more than 60 debuffs on the boss / tab-targeted to an add without any DoTs / etc.)? No DWT/60sec dps punishment.
  • DWT came up but you hit Aetherflow first (a habit most of us learned during 3.X, and old habits are hard to break)? DWT, but still 60sec dps punishment.
  • Die, for any reason whatsoever? Lose all progress built towards Bahamut Trance and start from scratch: over 120secs of dps punishment, on top of your rez weakness.
The 4.0 class changes were announced as making the classes simpler to play so that the gap between the dps of a casual player and an expert would shrink, but make one little screw up in 4.0 SMN's rotation and that dps gap is larger than ever.