Really you have three logical ways forward and one of them involve anything as silly as "if we keep calling it a game we are exempt"
a) The MtGox model. becomes licensed and regulated.  Most likely it will be insanely expensive, time consuming, and difficult.  Even if licensed your business model would need to change radically (hint there are no anonymous investments in the US, so called "bearer" bonds/notes have been prohibited for the better part of 40 years).  I just include this option for completeness.

b) The PokerStars model.  ACTIVELY exclude US residents, citizens, and entities from either listing or trading.  Simply having a checkbox "I am not a US resident" is likely not sufficient, just ask the foreign online poker sites that the DOJ took down (servers, companies, and bank accounts all in non-US soil and the DOJ got sufficient help from governments where the activity was legal to seize assets in excess of >$500 million).  You likely will need to consult with SEC on what would provide you a safe harbor exception but based on online poker's fallout I would imagine they would look for policies which require proof of non-US residence and actively blocking US based IP addresses.

c) The SR model. It is illegal and so what.  SR doesn't try to pretend they are a "game" that is just an idiotic half step.  Make sure your servers, operator's identities, assets, and operations are sufficiently shielded that prosecution becomes difficulty if not impossible.  Note that the SR wouldn't exist if they tried to pretend US laws didn't apply, that is just dumb.  They embrace the illegality of their actions AND are very conscious that lots of agencies with lots of resources would love nothing more than to shut them down forever.  I am sure that provides a lot of motivation to ensure they are diligent in keeping themselves shielded.  Nobody on the SR has to check a box saying this is just a "indirect delivery game", everyone is a grown up and they know what is going on.