First, let me start off by saying I really like the S3 rules, I think the officiating team has done a great job of creating a system where everyone has a niche to fight for points in, not just the top guys. I think that is reflected in the participation we are getting, and I don't see any places that need major rule changes.
The two places that have given me some heartburn are team points and retirement rules, neither of which have a clear cut solution, both have strong pros and cons.
Regarding retirements:
The currently rules are a very liberal form of FIA superally rules. The objective for this in the WRC is to attract and retain competitors, just like in the RDRC analog. The manufacturers spend insane amounts of money on these programs and have very limited testing opportunities. The drivers have very limited time to practice in their cars, and this is why you will see the WRC teams at regional rallies at the start of the season. Superally makes it so when a team goes out on day one, they still have development time on the car and seat time for the driver, they do not lose this vital practice time. The fans and sponsors get to see the cars carry on, and the top teams continue to get press coverage.
Being able to crash out on a stage and continue on adds a lot of accessibility to the RDRC, and lowers the difficulty considerably. However we do not need the practice or development time, we car run a stage and work on car setups whenever we want.
If superally attracts competitors, then it has a lot of value. However, nothing makes me roll my eyes more than getting beat on a rally by someone who completely destroyed their car to the point of not being able to finish a stage. That is not rally to me, we have turned it into a string of time trials where one stage has very little bearing on the next stages. In fact I can see situations where it would be more advantageous to just retire on the stage you took damage on and come back with a fresh car, losing less time than if you were to push on thru 3 more stages to service with a broken car.
The current rules encourage and even require a driving style where you are 100% at all times. This puts the slower drivers at a real disadvantage since they are forced to push all the time instead of driving within their limits and ensuring they finish without crashing. There are no scenarios where being conservative is the correct strategy when someone that is faster than you can totally destroy their car, yet finish above you in the overall classification.
That being said, there is plenty of opportunity for people that want proper traditional rally in the Rallyesim rallies. They are multiday, and retirement from a stage means retirement from a leg. With that in mind, I think there is room for a softer ruleset as the people that want a harder ruleset have an outlet for that already.
So I am in support of DNF stage = DNF rally, but not at the expense of participation.