Anyone who sees them self as a Constitutionalist republican (with a small R) should be in favor of changing the filibuster rule it back. The more that we rely on 50% +1 to govern, the more we move toward a populist Democracy and away from a Constitutional Republic.
The most important point is that Obama has two years to go and will no doubt try to pack every court with super-liberal judges. The goal of the Senate GOP is to stop that. With the 50 vote rule in place he will get a lot more nominees through. The 48 donks will only need 3 traitors to get his appointments through. If they go back to the 60 vote rule, then the bar is much higher, and his plot to court-pack will likely be foiled.
If the GOP wins the Whitehouse and holds the Senate then they can go to the 50 vote simple majority at that time. If Hillary wins stay with the 60.
Seems like a smart move to me. It's what Donks do: constantly move the rules to achieve your political goals without concern about precedent or tradition. This *could* be the start of GOP hardball, not the cave-in people seem to be suspecting.