On OKCoin the price is already a year-long low, back to the value of 13 months ago.
Feels funny for me to be saying this, but I don't think BTC is "done". Only "BTC in China" seems to be on the way out. Russia may soon ban bitcoin too, but I am not aware of that being a large market. Even with no new markets, Bitcoin will probably survive in the West.
I would not dare guess a price, though, and its potential for e-commerce may remain small.