This question is eminently contextual.
If your online community matches a neighborhood, a city or villages in a valley for example, diversity is probably better as it already exists in the community.
If your community is about stuff, for example about crafts or music, diversity is certainly great, since nobody will use high heels the same way—yes, high heels, you gotta see Kim Gordon play the bass with her high heels.
If you’re a developer community, a little diversity is good, but too much diversity would make the Not Invented Here (NIH) syndrome a pain to deal with. 
It really depends on the type of your community and your goals.
If I had to say in general I appreciate more diversity.