the only problem with your system is that it is going to be easy for people to abuse it by forming clicks.
if a group of people decides to team up and then they only play one another and nobody else then they are going to benefit. This will mean that the more games they play against one another the higher their rankings are going to be.
This is because yahoo's reward for winning far outweights it punishment for losing. The amount of points one gets for winning far exceeds the amount of points one drops when one loses.
This will favour any group of people when they form clicks. By playing one another many times over in their click they build up one another's points.
Sure they may agree to play the others now and then but even if they lose it wont matter since they can always go back and rebuild their ranking after a loss to someone outside their team.
That is why I am in favour of force and limit. You just have to play everyone. And you can only play any one person twice.
This way people will be discouraged from teaming up as it they would not gain as much from just two games against each other as they would from say a hundred games.
The whole problem is the way yahoo punish and reward defeat and victory. Your idea would have been good if yahoo had subtracted as heavily from someone who loses as yahoo gives to someone who wins. just try it. take someone with a rank similar to your own and see how little is subtracted from the loser but how much is gained by the winner.
That is absolutely untrue. The losers lose just as many points as the winners win. Cliques wouldn't help anyone.