One could argue that the Ukraine crisis represents a net loss for Putin - he had a reliably pro-Moscow guy in charge, only to lose him. He's only regained the Crimea and a small part of the east since. But in any case, was Bush as weak in 2008 as you think Obama was for allowing Russia to invade Georgina?
What we have to understand is that with the brief exception of the 90s, Russia has for centuries, and for understandable reasons of security, dominated the countries on its immediate frontier. Doing so is the top national security objective for any regime in Moscow, whoever runs it. Likewise, Moscow has for two hundred years maintained an interest in the Middle East, and its involvement in Syria is simply Russia re-exerting herself after a brief hiatus.
Conversely, Ukraine, Georgia, and to a lesser extent Syria, are just not high priority national security interests for the USA, no matter who is in charge in DC.