Autofill incentive to NOT troll.
A lot of people complain that players use troll picks when they get Autofilled. The LOL community looks down on Autofill because of this and that they don't want to play support.
What if there is some incentive to win a game that you get Autofilled? Maybe an IP bonus or loot bonus for the player that got autofilled? Maybe: 50% percent chance getting a 2x or 3x IP bonus. 45% chance of key drop. 5% chance of free chest.
With autofill incentives, the LOL community might start to accept the Autofill feature, find a desire to pick a good support champion and try to win.