I think BitUSD is the key.
I agree.. I also think bitCNY would be wildly successful given the daily volume. Since one of the hurdles for many people with BTC is value as they don't understand the conversion, bitUSD would make it very easy for them.
And I know I've said this before but if I was a precious metals dealer (and buyer) I'd love bitGLD. You'd no longer have to use USD as an intermediary (USD>GLD>USD,etc) or worry about the price/ratio fluctuations and you could focus strictly on the premiums.. "Gold rounds now only 1.05bitGLD!"
There are three main breakthroughs which could take Bitshares to 25 cents-$1.
1) The market peg has to work. It appears that the market believes it will work and is investing accordingly in prepare for initial takeoff.
2) There has to be Ripple IOU Gateways so that BitBTC can become real BTC, BitGLD can become real Gold.
3) Interest on BitAssets.
I think we only need 2 out of the 3 to take on Litecoin but if we get all 3 there isn't really anything else out there which can compete with Bitshares.
Imagine making trades in Bitshares and at the push of a button it goes through the Gateway and the Bitcoins go to your Bitcoin address, the USD to your bank account, the Gold to your physical storage vault. It's almost too good to be true to have that functionality.
At that point I could see billions pouring in... but we have to always remember that we are in a competition to innovate. It's not about first mover advantage because Litecoin had that on all these altcoins. It's about continuous innovation combined with community enrichment (the secret sauce).