Concept for Balancing Ranked

Basically a system which rewards you, during a match, for meeting certain milestones. If you are playing a tank, for instance, You could be rewarded for tanking certain amounts of damage which would be tiered (so after getting to lets say 1000 damage taken you would get one point and then 2000 [x2 of previous] would give you 2 points [also times 2 of previous] and so on) and you would have various accomplishments accommodating play style and the champs specific strengths. At the end of the game your total amount of points would translate into your performance rating and the amount of LP you would get. These achievements would be based around what every champ would be based around where each champ is supposed to be doing (so tanks would be focused around taking damage and a little on damage done [ to encourage front lining] adc's would be based around farming, surviving and doing damage, so on and so forth). Hope this concept takes. :)