"The key goal is combining bombing with a realistic land campaign, which will prove tricky. But a land campaign without air support will be a disaster. Bombing is vital."
Ok, you have a point regarding bombing pinning down fighters. But a land campaign without bombing is a perfectly viable strategy - it merely requires a land force to do the job - Daesh have demonstrated this by being there in the first place.
But if you're actually planning a land campaign, who is going to provide the troops? The Syrian Army and Free Syrian Army are both already engaged; as is Hizbulah and some Iraqi militias (ignoring the Kurds here, as they have no international sponsor) Does Iran/Turkey/Saudi Arabia plan to do any more than fund these militias? Does Russia/NATO?
As far as i can tell, there is no land campaign planned. Russia plans to push Assad into a position where he can retake territory held by non-Daesh rebels - presumably hoping to crush Daesh later when the west wants that. In the meanwhile more refugees will he created by this civil war - Assad and anti-Assad forces will push for territorial gains, and bombing will make more places unlivable.
In the short term no bombing campaign promises to reduce the number of refugees. Eventually, IF territory can be taken, then an air campaign might be worthwhile. Is France now sending in troops (while Ireland pretends to be neutral and sends peacekeepers to Mali to relieve the French troops stationed there and allow them be deployed elsewhere on a NATO mission...) is Turkey being pushed to help end the civil war? (As opposed to bombing the one neutral party - who while abandoned by Assad haven't declared against him, so they can still make peace if Assad were to win this civil war - and yes, we should talk about Turkey, as they have the second largest army in NATO, about a third of it is sitting on the Syrian/Iraqi border)