My 5 cents.
Russian economics is taking another hard dive, so they need to keep their diplomatic face by pretending they influencing global politics. Though, they're going more and more for a militarism in country, so they must keep the population in constant readiness for conflicts. There will be no unrest inside country if leaders talk about constant threats outside the Russia.
About missles - no evidence or proofs about intrecepted ones were given by the way. Russian media were caught on lie so many times here in Ukraine, so why not they can make the same in Syria, lies lies.
What we have in Syria is another little local war without high chance of getting global, the sides will keep challenging each other on both diplomatic and military fields. Remember the episode, where US troops destroyed russian troops moving to the oil fields? What action Russia took? Nothing.