The Syrian National Coalition (SNC), the fractured exile opposition, is respected within the Syrian rebellion as a means to facilitate defections and to bring attention to the cause – but for little else. Generally speaking, no one in Syria takes orders from the SNC. It is a waste of time to continue working toward negotiating any kind of deal between the regime and the exile opposition, because they do not have influence on the ground.
There has also been fierce debate as to whether the SNC should even partake in the upcoming Geneva talks with the Assad regime. The SNC should continue coordinating the refugee crisis and stop wasting resources on petty internal debate and negotiations. Any treaty between the SNC and the regime will be ignored by all factions on the ground.
The US should continue to work with the SNC, since they will play some role in the future, but the US should realize that the group is unlikely to ever comprise the Syrian government. The exile groups are most useful in helping the refugee populations outside of Syria and as a forum for activists and the collection of casualty figures.