Simple way to fix toxicity in ranked

You lose less MMR the longer the game goes.

The only sort of trolling I could think of is someone deliberately extending what, in a personal opinion, may be a garen-teed surrender at 20 game... but is it really trolling to just play to the best of your abilities and stave off defeat as much as humanely possible?

Seems like a simple tweak that even if it's minimal in the actual effect on MMR, might encourage people to be less toxic to begin with.