I think it's better that riot has a system that won't/can't ban int feeders/trollers because

let's think about the opposite. A system that's a little to heavy handed with banning people and starts banning legitimately poor players who are honestly trying their hardest. Just think about that for a moment. How many players would get unjustly banned from the game just because they weren't good enough? Is that justified by banning a small minority of int feeders/trollers?

I think it doesn't.

That being said the tahm kench/anivia duo is something else entirely. I think that overly suspicious cases like their's should attract some sort of manual inquiry to see what is up because those people's actions are unacceptable.