Donphan would be a really nice presence to have in UU - 90 HP / 120 Atk / 120 Def is pretty great. Yanmega sounds like it could fit in well with the current hype over Shaymin. A 4x resistance to Grass is cool, but pity it comes with the 4x Rock weakness. Regirock, Registeel, Regice, Chansey, even Clefable and Milotic stop it pretty easily, and the Stealth Rock quad weakness is crippling, so my initial opinion is that it would probably be OK in the tier. That said, Alakazam isn't all that different from Espeon...