Personally, I think making mixers illegal would have a tremendously positive effect on this forum.  It would likely cut down on wannabe scammers, spam, and harassment from bored signature spammers looking to stir up drama for more reasons to post.  

There are privacy coins people can use already.  Tangling Bitcoin up with money laundering and defending it so you can make a couple bucks to spam here while pretending it's a privacy issue seems pretty selfish to me.