The project is really impressive, you have some truly beautiful examples in the gallery. I see what you mean that user content creation doesn't seem easily accessible enough to hit Minecraft's level of self-marketing. But there is tremendous potential I think once you reach a more fleshed-out demo. Hope to see that soon.
Yes, I don't think I will ever achieve Minecraft's level of success, in part due to the fact that I'm designing something relatively niche and for a less broad age range. But still, I'm curious to see what the potential of it is.