Originally Posted by Fat Annoyer
Whimsicott will be easily dealt with in my opinion. Priority Encore is easily predictable and any Grass-types will counter it cold. A possible SubSeed set with Hurricane might be cool to damage Grass-types that would otherwise wall it cold, but I doubt an uninvested Hurricane will do much damage. Tailwind (<3) will get another user that isn't a bird/kacaw.
Weather teams will also be better in this metagame. Whimsicott can provide them priority weather while also giving a free switch-in with Memento and Whimsicott can abuse Rain via Hurricane.
I'm not too certain Whimsicott will be anything resembling "healthy" to NU. Boosting the capabilities of priority weather and being able to abuse Rain via Hurricane alone is somewhat of a "this thing is going to get tons of use". Grass-types don't necessarily wall it cold (I combine Priority Taunt, Toxic, and Stun Spore - not even Sap Sippers evade affliction, and switch-ins to them will be colossally predictable because how common SubSeed will also be). Whimsicott can do SubSeed slightly better than the Harvest users (Exeggutor and Tropius) due to priority in both moves, overall better base Speed, and no quadruple weaknesses to Bug and Ice, respectively, to worry about. While Whimsicott doesn't get to use infinite Sitrus Berries, it isn't overly reliant on them.
That said, some sets of Whimsicott are going to be manageable moreso than others. But it does give competition to Liepard and Volbeat for a job they otherwise didn't have trouble doing. The latter has to worry about being Taunt bait now. Whimsicott's base Speed, often uninvested, is 116. Liepard's base Speed, for comparison purposes, is 106. Another Prankster of note is Murkrow, whose base Speed is only 91. Whimsicott can simply Taunt them and then have a field day afterward!