I dunno, i just think that body modification will always be just that: modification. It will always be viewed with a certian amount of stigma because it is out of the ordinary.
As for separation of self and fassion...ehh really? I was always under the impression that we are our actions rather than our thoughts. If you chose to present yourself a certian way that is a an action and thus an avenue for people to interpret who you are. I'm pretty sure that fashion designers pour their hearts and souls into their work rather than just trying to make something look cool.
Maybe to clarify ill offer this. Would one lip piercing make me write you off as someone i want to know...Absoloutly not, if the person seemed like they had something postitive to offer I would look past the oddity it and try to get to know who is underneath. If i found the person to be well adjusted, stable and intresting, i would find it even more curious why they would chose to present themselves in such a way. While the relationship may function perfectly well i would always wonder what motivation caused that choice.
I refuse to believe that an alteration of self that requires pain, risk of infection, and a change of self image is an off the cuff decision. I would wager that you didnt know how you wanted to change the impression you create, but you knew that you wanted to change it, and what response you were looking to extract. So its not so much the peircing itself, but the reaction you could elicit. I think your argument would hold water in the case of putting on unique shoes or clothes, but causeing physical alteration to your body is a different issue.
Furthermore while society may be following the track you outline, a social liberalization of sorts, i dont believe that it will ever become the 'norm'. Firstly becuase people alter themselves to ALTER themselves and escape the norm. Secondly because while some things change others dont. Business for example has remained remarkably stagnant in terms of attire for decades. Asside from casual fridays (which are on the decline) industry has remained fixated on the suit and tie uniform. Why? Suits have a stigma of power attached to them, not to mention that they tend to make fat men look skinny (super convenient).
I just feel bad for people trying to fight the power of societal norms. I tried to do it when i was younger and more foolish. I am still not wise but i have come to recognise battles i can win and battles that are beyond me. Does the social rouge in the local mall, swathed in absurd dress, bearing a face full of metal change my preconceptions about norms...no. Does a well articulated arument about a need to throw asside our unsubstanciated intrenched ideals change my mind...maybe it does. Its all about picking your battles to win the larger wars.