By and large, I’d prefer it if more people did not hold supernatural beliefs—or at least, if they did not hold politically potent supernatural beliefs. (While I’m at it, I’d also like world peace, for my knees to suddenly not show the effects of my age on the basketball court, and so on and so forth.)
I’m not sure it matters much how such nonbelief would come about. Given my general cynicism about the human race, I don’t expect that any widespread nonbelief would be due to careful, reflective rejection of supernatural claims. Sometimes I run into hopes that better science education, for example, might help—if more people absorbed a scientific outlook, they should be more critical of unsubstantiated fantastic claims about gods and revelations. But then, my experience suggests that broad-based, in-depth, quality science education is too resource-intensive to be realistically possible any time soon. And even for those small segments of the population today for which science education is available, I’m not sure it can make a lot of difference. Thinking scientifically across the board is too difficult, and religion too easily finds the many loopholes it can exploit to insinuate itself into normal human minds.
I can’t get much excited about such a scenario either. In any case, we’re almost certain to continue to collectively behave like morons. If religion were to wane, we’d just have one color fade a bit in a wide spectrum of human folly.