This should be moved to PokeLab.
Cresselia- Cloud 9, Will-o-wisp
Sandstorm and Rain Dance (in Ubers) are the only things holding Cresselia back, other than Pursuit. Both of these alleviate her problems.
Corsola-
Stat changes:
HP 155
Atk 95
Def 120
SpA 5
SpD 120
Spe 5
Movepool additions: Gyro Ball, Spikes, Trick Room, Baton Pass.
The idea here is rather obvious, create a tank with some utility that no other tank in the game has. With access to many stat boosting moves including both Amnesia and Barrier, Explosion, Sucker Punch, a host of support moves, Natural Cure, great STAB, and Recover Corsola offers stalls an incredibly interesting option in their team. Its not without its weaknesses either, which is most evident by its weakness to Earthquake and fighting moves. Also note its ability to Baton Pass Ingrain.
Noctowl- Dark/Flying
HP 100
Atk 50
Def 50
SpA 75
SpD 115
Spe 120
Abilities: Compound Eyes, Insomnia
Movepool additions: Trick, Knock Off, Amnesia, Nasty Plot, Will-o-wisp, U-turn, Encore, Dark Pulse, False Tears, Imprison, Kinesis, Memento, Flatter, Taunt, Signal Beam, Confuse Ray, Shadow ball
Here I've crafted Noctowl as a great Anti-led, and gave him a far better typing to suit his Special Defense nature. Immune to Psyhich and Ground. as well as Resistent to Ghost, Grass and Dark provides him with the basic ability to be a defensive pokemon. Compound eyes generally is reserved for bugs, but I believe that it does aesthetically fit an Owl. As an anti-lead in the metagame we are crafting, Insomnia is the better choice as Jumpluff running around with Spore, as well as our Hypno all make Insomnia an incredibly useful ability. As an ingame status spreader, Compound Eyes is the better and much needed choice for Hypnosys. To make up for his lack of defense, he has Amensia, Roost, and Feather Dance. There are still some large things holding him back such as TTar, but hopefully a more balanced Metagame would open him up more room to breath as TTar might not be so dominate.
Shuckle-Arena Trap.
Move changes: Gyro Ball, Trick Room
Say hello to the OU Wobbufet. With Arena trap, Shuckle no longer relies on Wrap to play the trap game. His move pool adds to his support and offense options, allowing this set to aid far more than stall.