I know what you mean, I feel a bit like that too, but even if they've found Earth, that doesn't mean it's the end. There's still plenty of threads to tie up. If Earth's a wasteland, where will they turn to next? Will the humans and rebel Cylons remain (tenuous) allies, or begin taking their frustrations out on eachother? What about the other Cylons? Cavil was killed and the Hub was destroyed, but there are supposed to be millions of Cylons, so there must be more left out there, and they must be angry.