They wanted to put certain vicious elements in the story to make it a real life hard struggle but they couldn't make it.
I feel it was more complex than that. The underlying question was stated by Commander Adama, in the pilot: "do we deserve to survive?" Refined more into, "what kind of people are we?" as the series progressed. The way they initially dehumanized the Cylons, then as time went on, some of them realized that such a perspective was flawed, and defended their rights.
To me, the main character, is Baltar. A machiavellian atheist, who eventually learns to use religion to survive. Not a hero by any means. Just a very self-centered human, whose cut-throat pragmatism keeps him alive in a desperate situation.
The entire tone is set by the number on President Rosylin's wall: less than 50,00 people left in the human race. And the number is always going down.
The idea wasn't wrong, how it was applied that failed.
I feel it succeeded perfectly, at least for an american audience. Edward James Almos took the role seriously, and set the bar high for the rest of the cast.
I have watched the entire series three times now: once when it originally aired; once when I got the blu-ray set as a Christmas gift; and once with a friend(who was not a sci-fi lover), who couldn't get enough of it.