You won't have to worry about losing diversity, even if EVERYONE switched to pep it's not like every person who wants a prop is going to use one pep file.

It seems to me that most of the people who use pepakura are the ones who wouldn't have used any other medium if pep didn't exist. I mean if I didn't have pepakura, I probably wouldn't attempt any way of making an Iron Man helmet. As I was saying earlier it's an opportunity. But even with the same pep files, I've seen different people use my helmet files and come out with totally different looking helmet. Because of the bondoing stage they all come out looking different. Maybe not as different as pure scratch sculpts but there is still some interpretation to be seen. As far as incomplete helmets, eh, it's going to happen with any medium. Sometimes people get lazy, pepakura just makes it easier to have something cool that's incomplete lol. *cut, glue, BORED, stop*. So you can look at it as a loss of diversity, or as a chance for people to make something cool that they couldn't have made otherwise.
I'm not trying to change your mind, just sayin' what I think ^^
I started props when I turned 17, and I just became 18 this month. To be honest I'm not the most knowledgable prop maker.:lol