I like some sort of weighted system where you get a few more points if you pick a driver that finishes 2nd. Then it tapers off till you get to the 5th driver.
The tricky part is getting the number of points awarded so that it's fair and remains competitive. Other options could be just pick 3 drivers and in the order they will finish. If you nail the driver and the placement you get a kicker, otherwise you get the single point for having someone in the top 3. Say maybe 8 additional points if you select the winner, 5 extra for picking the correct 2nd place driver and 3 extra points for correctly picking the 3rd place driver.
Prior to getting involved in this pool, I thought the other drivers had a greater chance of winning each week. It does appear that several of the racers are a lot more capable than the others, which is why we are now pretty much selecting the same drivers.