What if champion kill gold was based on K/D ratio.

That's the worst thing you can add to the game, not even ancient game design in DotA included something like this, and it's for the best why it didn't.

Not to mention, kill streaks and bounty exists for a reason. I am not sure why this is even necessary.

Just to make sure, you do know how the existing bounty system works right?

I've had games where it wasn't even worth leaving the minion wave to kill the inter anymore since they were so worthless.