Thanks for posting this series! Your hypothetical did lead me to ponder quite a bit. I think it misses an important point: the hypothetical context that a group of analyses would face under real world conditions.
In the red card study, the analyst teams were not facing the prospect of publication bias, they were merely tasked with answering a specific research question given a dataset. Had the intervention been two groups: 15 teams to tasked with getting published as quickly as possible using any analytical technique that seems best and 14 teams preregister the best analytical technique to answer the question given the variables available (with data provided after preregistration), then I certainly would trust the preregistered results more than those that were under pressure to find the most exciting results possible. Knowing that one arm of the group is only likely to come up with the most extreme answer certainly changes my opinion about its credibility.
The act of preregistration is not magical. It does not, by itself, change the future rigor of the results*. It merely creates a clear distinction between planned and unplanned analyses. Is the reviewer-recommended, unplanned analysis better than the preregistered one? Maybe**. But readers are only able to make that determination if they see "I planned X (results are Y), I ended up doing Z (results are Q)" instead of the status quo of only showing the final analytical decision.
Finally, I think adding a multi-verse approach of presenting the results of all possible analyses is a great recommendation. Open data is likely to enable such a future.
*Well, perhaps it does insomuch as thorough planning improves any process. Also not mentioned in the above post is the benefit of opening the file drawer.
**I'm much more likely to think so if the reviewer makes that recommendation before knowing the main trends in the dataset.