obama is actually right that the leadership in syria needs to be changed, but what the western media is ignoring is that putin actually agrees with him. it's a difference in approach, not in preferred outcome. nor is the issue assad, exactly, but the military junta that props him up; assad is in truth a mostly powerless figurehead.
suppose we wake up tomorrow and isis is destroyed and syria's borders are again secured. can that be the end of the war? in truth, it cannot. the devastation created by these foreign mercenary fighters is far too great to be forgiven by the very same people that have been waging the war. i'm not going to talk about cultural realities. it transcends that. syria is defending itself against an existential threat; destroying isis does not eliminate that existential threat, it only abolishes it's most outward manifestation. if you leave the generals in power, they will plot their revenge by turning the tables in launching an attack on riyadh.
even that is likely not enough. the real change that is required is in saudi arabia. the only way to truly end the conflict in syria is through lasting regime change in saudi arabia.
but, in the short run, to at least end the current phase of hostilities, syria cannot be left in tact to fester hostilities and plot it's revenge. that is obvious to everyone. the difference is that putin wants to see the state transitioned peacefully through the introduction of democracy, and obama wants to tear the state down by force.
https://www.youtube.com/watch?v=RDx8Bvlw3es