Wouldn't Zerocoin be at risk at getting totally banned in the US. From the last New York hearings they seemed to keep stressing how they hate fully anonymous coins and tumblers, but gave bitcoin benefit of the doubt because of the public ledger..
It's a decent point, but does it necessarily have a negative impact on price ?
BTC did quite well 0-$1200 with mainly the Chinese and Ukranians providing the price discovery. Not much US involvement there.
That said, regulation will legitimise the arena and acceptance - still, anonymity may have its niche ... and perhaps there wont be such a proliferation of copycats.