Lock out certain Troops from donations.
I'm sure I'm not the only person who makes a Request, and labels it along the lines of "No Giants" or "Defense Troops please". Only to have some idiot suddenly join the Clan, donate all their Giants/Hogs, and then leave before they can get kicked.
So my idea, is to have an option to Lock out certain troops from being Donated to you.
So, I make a Request, I select it so Giants and Hogs are Locked out. Someone then tries to donate Giants and Hogs to me, but it tells them that these Troops cannot be Donated to this player. Their plan to ruin/lack of ability to read my request is foiled, they leave the clan frustrated that they can no longer be an arsehole, they eventually learn that they have to become a functional and supportive member of the Clash of Clans community.
No more wasted Requests.
Everyone wins.