Whilst I will be amongst the first to wave the flag of the right to self-promotion and expression, I have been a little peery of cosplay in general. I don't think it's harmful in any way, shape, or form, but I do believe that it is fairly symptomatic of the larger problem of being a cog in the mass consumption machine.
I think there was a study 5 years back, and it showed that as of the late 2000s the average exposure a person has in a developed nation is about 1.8 hours of advertisement per day. This idea that there is a million pressures on how to dress, what to wear, how to rate others on presentation, how to act, what is desireable, being told what is necessary, so on and so forth.
I think there is a direct correlation to the rise of cosplay and the modern world of advertisement and consumption, and I think it is because people (young people particular) feel at odds with how they feel they should look, act or be judged by others.
I doubt that in a society that put less pressures on having the right dress, the right perfume, the right haircut, the right pair of shoes, etc ... I doubt cosplay would be as big a thing as it is now. But in the same way that buying into a perfectly constructed corporate image of how to be is dangerous for self-esteem, I think that the same dangers can be found into looking into the fantastic to find role models to emulate to what would amount in any other situation to be a fairly creepy degree.
I think cosplay is fun, I think that's what it's meant to be, but I think the reason why it's fun is because it rebels against consumer culture by EMULATING consumer culture. The world within the looking glass. But I doubt it would be so popular if there wasn't such a well designed corporate slogan of 'how to be, or else ...'