My signature says it all. Those things are in order of importance. So this entire conversation takes place in the realm of the least important factor, the gun.
That said, the most common fallacy promoted by defensive revolver shooters is that if they just make their shots count they will be fine. We like to assume we will get one or two bad guys who cease their felonious acts as soon as they start leaking. That may be the case, or it may not be. There may be 6 guys or there may be one guy on drugs, or you may miss 6 times and still have time to shoot a 7th.
It's a game of scenarios and probabilities, and by far the most common outcome is that we won't ever need to shoot a gun in defense. The same logic that brings you to the conclusion that you should carry a gun should also bring you to the conclusion that you should carry the most gun you can. If you think you need a gun but that 6 shots should be enough, you are picking and choosing the logic you want to follow.
But, ultimately, those toting around 5-shot J-frames are better prepared than 95% of the population, and in reality it will likely be all they ever need, since they won't ever need anything.
And most importantly, you are best served focusing on Mindset, Tactics, and Skill before worrying about what gun you have.