Scrutiny by regulatory bodies is bullish because either (1) legit operators emerge with government approval or (2) it becomes clear that the government is unable to control bitcoin.
It is still a prob with we are left with 1 or 2 legit operators but it turns out only ~5% of traders are legit (not involved in illegal stuff).
1 or 2 legit operators is all it will take to open the flood gates to the mainstream
if it is revealed that only a small minority are 'legit' traders and the winklevii are solely responsible for bid-walling (start sept-oct 2012 thru feb 2013), then the mainstream will not give a crap about btc.
silk road and winklevii make bitcoin a juicier story not a smaller one
sure mainstream media, but mainstream-potential-investor will not be interested.
who wouldn't love some tax free money to buy drugs, while also having a chance to hop on "the next big thing"?