Why could not have Obama offered such a solution publicly? Was he afraid he'd be turned down? Even so, he would have had the argument that he offered a diplomatic solution rather than just a military one. Did Syria's turndown of the Qatari pipeline (wanted by the Saudis) have any influence over Obama's approach?
I'm sure Putin is not being benevolent ... he just wants to keep his country from getting into a ME war, and, of course, gain world stature by being the arbiter of a grand compromise that saves face for all concerned.
Obama could not have suggested it. It would have been a beginning negotiating point rather than what we hope to be is the end result. We should not have been negotiating anyways. Obama acted as he ought to have. Predictability in world politics is very good.
It was in Russian interests to not have an attack occur, but Putin does deserve credit, he stepped in and found a solution that was acceptable to everyone. Kudos to all the actors involved also, it is not easy to step back from ones own position to accept a compromise.
Just don't forget that if Syria does not act in good faith and disarm its chemical weapons the strike option will be there and have more credibility as the only viable option.