A lot of people who are requesting lv. 9 Reshirams are nine-year-olds with a god complex, though some of them could be attempting to find new GTS glitches such as cloning and whatnot. I agree with Kyuuketsuki. Instead of completely banning these requests, put a filter on. "Searching for: Pikachu Not Willing to Trade: Arceus, Manaphy, etc. (maybe up to ten?)".
They should also add more search options:
1: DW Ability (If available)
3: 31 IVs in each stat (Checking boxes for combos)
4: Event Section (Event trades only)
5: Nickname Search