Why don't legends have defensive ratings?
I know we can't place them in gyms, but we do have to fight them. Defensive ratings would show the strongest movesets to fight against.
I would want it more for the opposite. I can probe ahead of time to see what moves a raid boss has, then if it is an easier moveset I can show people the ranking and plead with them to break into smaller groups so we can get more balls and more rewards.
My only other source right now is http://www.pogomoves.com but they have a straw poll going now "Vote if legendaries should be removed from defender list!" and it appears they are going to be removing defensive movesets.