That's not actually a bad suggestion - but, you've used that word which brings shivers to WRC top brass. The 'E' word......
Whisper it..... Endurance. And anyway, define Endurance. In my view, any event with 500km+ of special stages is endurance. Surely there is room for 2-3 Endurance events in a 12-13 round series?

I've also seen a suggestion to follow the example of FiS Cross Country ski-ing; I'm not sure that would work. But it would be better than this 'shoot out' concept.