An ELO system where a loss of the game doesn't mean you lose elo.

Can we get an ELO system that is a bit more dynamic? I just lost a game because our 5th person left some 15 mins into the game (I got an S+ rating). It took the other team 50 mins and 2 Barons to beat us. Yes, there's probably something we could have done if our ADC didn't enjoy the way her ears rubbed against the inner lining of her small intestine but that folks is ELO Hell.

Some things I'd like to see a new system incorporate, especially at the lower ELO levels:

• S ratings enable you to gain ELO even in the case of a loss (maybe this goes even as low as A+ but nothing too low).
• a game played with X% of the game down a person gives that % is LP loss reduction. Example, I'm set by normal calculations to lose 18 LP but I had a leaver that left 20 mins into a 50 min game. This means I played 60% without her. Then, 18 * .4 (the % played with the leaver) = 7.2 LP loss (rounded down?). I mean, my team stuck it out and played to the end. They should get something for not just /ff. You could also restrict this to any game that exceeds 25 minutes so that a team that does /ff won't get the loss reduction (so people can't game the system).

I wish I had a 3rd bullet point but that alone would make life a little easier at lower ELOs.