I agree with this, too...
Renowned fantasy author George R.R. Martin expressed his extreme disgust with the series' writers for producing this ending, saying on his livejournal: "Battlestar Galactica ends with 'God Did It.' Looks like somebody skipped Writing 101, when you learn that a deus ex machina is a crappy way to end a story...Yeah, yeah, sometimes the journey is its own reward. I certainly enjoyed much of the journey with BSG...but damn it, doesn't anybody know how to write an ending any more? Writing 101, kids. Adam and Eve, God Did It, It Was All a Dream? I've seen Clarion students left stunned and bleeding for turning in stories with those endings."
I think the "Danger, Will Robinson" moment to the show really came with some mix of the Final Five and, worst of all, when Ellen Tigh was revealed at the Final Fifth. Ellen "What the Fuck?" Tigh? She's the Fifth Cylon? Who could possibly give a shit about that? When that happened, I was like "Oh, no...." and it spoke volumes of what was coming down the pike. And really, the whole Final Five (hate that term for them, btw -- makes them sound like a playoff in basketball) plotline was a whole lot of nothing -- none of those Final Fivers really did a hell of a lot to justify the buildup surrounding them. Especially since all but two of them basically continue on being what they already were beforehand, more or less. Weak. The story got hijacked by the God(tm) shit and it gutted and filleted the story. And what's Starbuck? Is she a goddamned ghost? Or another of those fucking "angels" that get touted? Whatever. Lame. Weak. Bad.
Nothing worse than a bad case of Writer's Hand intruding on a story. I always avoid this in my stories, because it's annoying to have something happen because the Writer wants it to, or is at wit's end and cops out with "Because I said so." Lame. Some serious writer's fatigue must have set in on some level, or else the writers wrote themselves into a corner and decided to pull the ripcord and hope the cop-out wasn't caught by the majority of viewers/fans.
Seeing that ending made me very glad I didn't watch the show real-time, or I'd have been hugely pissed and would've felt cheated. Even when they were pimping out God(tm) in the story, I kept hoping that we'd see the robot God(tm) as some grand AI (and, let's be honest, the closest we'd ever come to a god in this world is an AI -- the combination of omniscience, omnipresence, and omnipotence that equals "God" would be a singular quality of a powerful AI).
But, instead, it's kept all mystical and behind the curtain, subsuming the entire storyline and all of the characters, scuttling "Galactica." Whatever. Big disappointment. The first two seasons are solid. Third season is entertaining, before Hell's Bells being sounding and drowning everything out.