I find that:
Whimsicott
-ENCORE
-Substitute
-Leech Seed
-COTTON GUARD
Ability: Prankster
Item: Leftovers
Nature: Bold / Impish
EVs: 252 HP / 252 Def / 4 SpD
is a lot more annoying (It worked wonders for me in BW2). It allows you to wall physical (stat boosters) to no end, specially because whimsy is immune to outrage...~
I've been using a very similar set:
Whimsicott (M) @ Big Root
Ability: Prankster
EVs: 252 HP / 252 Def / 4 Spd
Bold Nature
- Giga Drain/Substitute
- Encore
- Leech Seed
- Cotton Guard
With Gen 6, Whimsicott was given a VERY nice boost by becoming Grass-Fairy type. Because of its Prankster ability and very nice support movepool, Whimsicott actually has a lot of potential as a physical wall. With its move Cotton Guard, it gets a +3 boost to Defense per use, essentially giving it a whopping 737 defense in a single turn (thanks to nature and EVs)! The second turn, it increases to a ridiculous 1180 Defense. Two turns = 1180 Defense. Also, since Prankster gives Cotton Guard priority, it can very easily get that boost. Leech Seed is its primary damage move, and Giga Drain is there for when there is nothing else to do but sit back and let the opponent wear itself out or switch. Priority Encore can wreak havoc as well, locking an opponent into a move like Stealth Rock for several turns of Leech Seed Damage, and giving Whimsicott a chance to maximum its defense with a whole two Cotton Guards. Believe it or not, I've stalled out entire teams with Whimsicott, simply because it's so... unexpected. Even Mega-Kangaskhan (unless it's carrying Fire/Ice Punch, which is surprisingly rare) can't break through it. Big Root boosts the recovery amount from Leech Seed and Giga Drain, which is essential to stalling out the opponent. I go with Big Root over Leftovers because even after full HP EVs, Whimsicott doesn't have amazing HP (therefore you usually get more HP recovery from boosted Leech Seed). If Leech Seed gets down on a bulky target, it can restore huge portions of Whimsicott's health per turn. You can run Substitute over Giga Drain to avoid Toxic, which really messes with this set. The nice thing about Substitute is that Whimsicott's defense is factored in, so after a Cotton Guard boost or two, its Subs become very difficult to break. Unfortunately, Taunt goes through Substitutes, and this set is pretty much useless against any Grass-type due to their immunity to Leech Seed. I'm really hoping that Whimsicott gets Draining Kiss when Pokebank launches, but its probably unlikely.
This set is best supported by Toxic Spikes and other residual damage dealers. It also works very well against Breloom and Smeargle leads, who usually start with a Spore. The best way to do it is to lead with something else, switch Whimsicott in to absorb the Spore (since it won't be affected, as spore is a Grass-type move), then use priority Encore, forcing the switch.