Well, our company manages a lot of tenants for our customers. But the most heard frustration is that policies can take a "long time" to apply. Whenever you force a sync, the policies are applied quicker. I believe it still could be faster. Other MDM solutions use agents and when a new policy is configured a trigger is sent out to all those agents. This makes the change to policies almost instant for all online clients. Also reporting on if policies are applied is always behind. Especially when you are testing and need to see the results before publishing policies to production, reporting should be almost instant in my opinion.