I don't know why I would bother watching the series if the mini made you so miserable. Let me tell you now that in the series, you're going to get more of what you saw in the mini, so just save yourself some time.
The Gaius Baltar character in the new series is probably one of the most interesting characters. He's completely insane. Or maybe he isn't. Reality and fantasy becomes a complete blur to him and somehow he manages to get thru it. I'd say there's definite depth to the characters and it becomes more evident as the series moves along.
As for shows ripping off one another, I suppose you can say BSG ripped off Star Wars, but does it stop there? Remember that SW is taken from a lot of other sources, so I don't see the point of arguing that angle, regardless if it's SW or not.