Syria’s southern rebels draw up new game plan

What the article makes clear is that the West and the Gulf countries have not been backing the rebels in the sense that they want them to succeed, but because to do nothing would be considered an outrage by their own people. The idea that the rebels were proxy forces that would carry out some unidentified policy of their masters rather than the revolution against Assad was always impossible to take seriously, all that could be done was neuter them by promising support and not delivering. That is still the threat, that the US will use the threat of the rebels to negotiate a transition that maintains Russian and Iranian domination of Syria without Assad, and sell out Syria permanently if they can get a deal.
"In contrast to the north and east, where Syria shares frontiers with Turkey and Iraq, the southern border with Jordan has been relatively well policed, preventing the kind of influx of foreign extremists that have aided the rise of ISIL and Al Nusra.
That had made the southern front the best hope for the West and Gulf States, and the moderate rebel groups they are backing, to bring pressure to bear on Iranian reinforced, Russian supplied regime forces in and around the capital, Damascus."