Hey,,, idea! Why not a system where you just get points equal to your position. I.e. 1st place gets '1', 2nd '2' and so on.
The person with lowest points at the end of the season wins the championship.
It's easy to understand and could even have little tweaks added. It would also punish unreliability (although apportioning blame for crashes could incur the wrath of a driver inheriting the points of the person he took out)
Rob W