I was really leaning close to no ban, since quickbans are pretty drastic, but cresselia is just too too good. Dual screens lunar dance is kind of neat but it's not broken; mesprit can run the exact same set and it's not even used. SubCM can be devastating with the right support but... so can a lot of other stuff. It honestly wasn't that impressive in my opinion. It's certainly a dangerous set but were it the only cresselia set I wouldn't consider it broken.
The set that makes cresselia broken in my opinion is simply the defensive set, and its ability to wall opponents with incredible bulk while crippling would be counters with paralysis and toxic. There really aren't very many pokemon that can break through Cresselia. Durant needs a choice band and hustle to guarantee a 2hko cresselia with super effective STAB (well... 64% of the time of course). SD Drapion sucks at everything else, and can't ohko Cresselia with a +2 Life Orb Crunch. Rotom can't even 2hko with Shadow Ball... against a physically defensive Cresselia. Again, these are all super effective STAB moves I'm listing. Cresselia is just way too bulky, and way too good at spreading status around, and it doesn't belong in the tier.
reyscarface: nails unluckiest man alive
Eternal: no ghosting Das