It's what I've said from the start. Season based points total is the best option. If that doesn't work at least make it an 8 car playoff with them all on the same side of the ladder. Non-playoff cars qualify on the other side. The final round between a playoff and non-playoff car is for money and trophy but no points. That helps take away from any <ahem> forced dive factor. They could also toss in bonus money to the non-playoff car with the best points total over the final playoff races.
We have had champs crowned who have only had to beat 2 countdown cars, we've had drivers win 8 races and not win a title. Instead of a season of importance they have made only 2 or 3 races matter. There is no longer the greatness of battling the heat, elevation, cold and everything else that happens in a season. Just get hot for a couple of races and you are good. We don't get legendary, we now praise mediocracy. With the low car counts you don't even have to make all the races the make the playoffs or even win a title.
The countdown seemed to tick off the hard core fan, the ones that go to multiple races and watch all season, but in return it didn't draw the new fan in. When the NHRA rolls into town, the casual fan comes to a race for that event. Who won the title last year is of no consequence to them, only who wins the race they are at. Whatever championship system they use doesn't matter to that fan. But in order to chase that fan, they alienated the die-hard fan.
I could live with a true 8-car playoff, although would much prefer a real season long champ. It might it get me going to more races again, as I am down to 1 NHRA race per year now. The year before the countdown I went to 4. Now I spend my money at other drag racing events.