This is the most concerning aspect to me. When your subculture is still niche, you won't get irate normies demanding change to what you consume. You don't get asinine censorship demands.

Look at video games, how it's sort of become one of the hubs of the culture war (think: gamergate). No matter what you think of that, it's true that it only happened in the first place because people who were not initially part of that niche culture forced their way in and demanded change from everyone else. Seniority doesn't matter. Fact is, you will get angry people trying to change everything if you get too mainstream, because people are outrageous control freaks.

What does this mean for anime as it gets more mainstream? This is harder to say since just about all of it is made in Japan. Even if people start complaining about it over here, how much of an impact will that have? How much of our niche culture will compromised and "reformed" as an act of appeasement to people who aren't okay with the "weirder" parts of anime culture?

Frankly, I'm not terribly optimistic about anime becoming mainstream. I think issues like I've described above have a chance of coming to the fore during the 2020 Olympics, as Japan tries to cross-promote their cultural stuff (anime, manga, music, etc.) along with the sporting events. By the mid 2020's, anime might already be on the path to drastic reform to appease the angry, vocal minority who were never a part of our niche group to begin with. Outsiders will demand change and they will get it eventually.