Whimsicott- a support pokemon without much support...
Resistance is good but not amazing, considering that Keldeo can probably manage this thing anyway. Weakness is okay, retreat is okay.
The first attack seems kind of interesting, like a quadruple-plus power that takes up an attack slot. Of course, this is assuming that the pokemon you are switching into A. actually needs to waste a turn attacking for the boost and B. is strong enough to get hit once in order to make full effect...
I can't see this card being terribly great in any condition, perhaps as a "Gyro Ball" type card into Stoutland BCR or Gothitelle EPO. One problem is that it doesn't say "your opponent's Pokemon", it says "the active Pokemon", so your opponent can just laugh and Switch or Retreat out of the Fluffy Tag condition.
It's a 3/10 for me. It has uses but I've never seen it played, and being a fragile stage 1 doesn't help terribly much.