I've said that even before the Ukraine crisis. Russia is just aggressive and blessed with weak neighbors in the west.
Although I disagree with the idea that Russia's Syria base is less than worthless. In a full-scale long war, it is surely subject to isolation and destruction.
But in peacetime it helps Russia project power into the eastern Mediterranean Sea to screen Russia from threats from this quarter.
And in war it would take time and Western resources to reduce the Russian military threat there.
Further, if Russia makes enough gains, perhaps Turkey decides it is not worth risking Russian wrath to block supply lines.
UPDATE: When weak, sowing discord in your potential enemies (or victims) helps a lot. Which is what Russia is doing:
Experts on national security painted a sinister picture for senators examining Russian meddling in the 2016 election, detailing the worldwide impact of fake news, smear campaigns and even killings they say could have ties to the Kremlin.
This is a longstanding and broad problem that Democrats only noticed when they were the target (and not that I believe Russia believed their effort would get Trump elected--they could read polls as well as the rest of us, and simply hoped to damage Clinton while damaging the appeal of our democracy as a model).