Was your issue with the fourth season the pacing and lesser action set pieces compared to previous seasons or was it more about possible story loopholes? Or maybe something else? I mentioned the pacing because I've heard that complaint from some BSG fans before.
In an attempt to avoid fulfilling RawKryptonite's prediction there, I'll keep it brief. It was largely the story loopholes, and the overall change in tone and story focus. Action was a component of that, but not the biggest part, I don't think. I felt it went from kind of a story of survival to a story of the mystic and supernatural.
And just to head off some comments I can see coming, I have no problem with mystic and supernatural stories, I just felt like it was not the show I got interested in at the start. Add that to what I consider to be lazy writing and enormous story loopholes, and it just didn't work for me.