(This is based on my understanding of how the leaver system works based on hearsay, so forgive me if it's inaccurate)

Consider the following game:

-Enemy team has someone disconnect at champ select, who never reconnects. The early disconnect means they cannot receive a loss because they were playing at a disadvantage, but can still receive a win if they succeed despite the uneven odds.
-10 minutes into the game someone on my team dies and ragequits since it's safe to do so. Two others see the quit message and decide they're going to quit too. Now it's 2v4. A couple minutes later it's 1v4. I can still receive a loss because the disconnects on my team happened 10-12 minutes into the game.

I receive a loss and the enemy team receives a win. I didn't deserve the loss because I can't win a 1v4, and the enemy team didn't deserve the win.

Once a game is safe to abandon it seems completely random whether anyone on either side is going to play the game to completion and wins and losses probably shouldn't be handed out.

The way the system is set up it almost creates an incentive for more people to leave past the first. If someone on the other team never connects I might as well quit right away so I don't end up having my time wasted if my team decides to quit later. It's really, really annoying when you play 30+ minutes of a 4v5 and the game is somehow relatively even and then someone else randomly quits and the game shifts in the other direction.

Potential Solutions:
-The game shouldn't be safe to leave just because someone on the other team left.
-Neither team should be able to receive a loss if someone disconnects early.
-The game shouldn't record stats if more than one person leaves.