We have an ability called Prankster. Having an ability called Trickster would be redundant. As for the other abilities. Has a chance of either being crippling or overpowered, depending on the Pokemon, nature, etc. How about making physical attacks being affected by special defense and special attacks being affected by defense, but still being based on the attacker's appropriate stat?
4e is not D&D, but WoW making a Disguise check. Pokemon Black Friend Code: 0605-2800-9952; Trainer Name: Solace; First Pokemon (roleplaying): Shiny Umbreon