About 90% of requests are impossible to meet do to event Pokemon species being blocked on the GTS. Please sign it's free and we might actually make the GTS a good place to get trades. If a Pokemon is unable to be deposited, it shouldn't be allowed to be requested
https://www.change.org/p/the-pokemon-company-game-freak-pokemon-x-and-y-gts-don-t-allow-players-to-request-event-special-pokemon-if-they-can-t-even-be-deposited