From a friend:

Jonah,
I agree completely with your thoughts on BSG. The writers thought they were going to be canceled after the 3rd season, so they had to come up absurd story lines to keep the series running. If you cut out 3.5 and 4.0 (essentially the filler of the last 22 episodes), the series has a better flow and pace to it. If they find Earth sometime soon after the algae planet episode the series concludes nicely (Baltar’s trial, mutiny, cylon resolution all in the last season).
The thing that drives me insane about BSG is the lack of continuity in the last season:
Earth was nuked 2000 years ago, yet there are bones and metal objects on the surface. However, Earth is uninhabitable. Caprica was nuked a year ago and cylons spend a good half of the first two seasons standing around sipping lattes and planting trees.
The hybrid is special because it is the only child of a human and cylon. However, Tyrol is a cylon, so suddenly someone else fathered his kid (if that was the case, why was Calley so worried that her child was a cylon?). Further proof Moore randomly chose four people at the end of season 3.
Roslin dying again – Roslin was dying until the hybrid’s blood cured her. Now the cancer magically reappears, but the Hybrid’s blood no longer works.
The moral complexity of Tigh killing his own wife is destroyed since Tigh is a cylon and his wife will come back to life.
The Cylons are now mortal because the resurrection ship was destroyed. Don’t tell me you found the key to everlasting life and lost the plans! However, they won’t be too mortal, because then how would Ellen come back?