*Plot spoilers below
While the show ended two years ago, I only now just got around to finishing the series. Here are some 'musings'...
1) The Show always presented a debate between monotheists, polytheists, and atheists on the question of God's existence. In the finale, it turns out the monotheists were right all along. What was not up for debate between the Humans and Cylons were the permissive sexual attitudes practiced on both sides. If there is a God or gods, the assumption was, he or they do not concern themselves with such trifles. In light of this persistent theme through five seasons of the show, the finale took a rather puzzling turn.
Flashbacks are presented depicting Caprica before the Cylon attack. We see Tigh, Ellen, and Adama at a club and Roslin considering having an affair. They're not living very admirable lives and their lives are depicted as banal. The suggestion is the attack and consequent struggle for survival afterwords brought forth the best out of them.
In the final scene of the episode, human civilization has returned back to the level (population, technology) it had reached in Caprica. God finds the same problems with this civilization as he had with Caprica. And the list of sins is rather traditional e.g. materialism, debauchery, etc. Ultimately, the Divine is not the Libertine the Show originally made him out to be.
2) After discovering Earth, the Humans and Cylons decide to give up the technology they possess and start all over. They will live simply and even intermingle with the human savages on earth. The hope is this will break the cycle of violence. The Final Five explained in a previous episode that Caprica's destruction and the ensuing aftermath was part of some sort of cyclical pattern. The implication is technology is the source of evil and Humans and Cylons can live in peace if they live without such relishes. It all sounds like Rousseau who argued that the advance of civilization was the regression of man. The 'noble' savage in the state of nature is morally good and it is civilization which corrupts him.
The conclusion takes place thousands of years later and we see civilization has developed in spite of Human/Cylon decision to forgo technology. And as I said in the previous point, this civilization has developed the same problems of the last one. This is because the source of evil is not in the material circumstances, but the human (or cylon) heart. Even if they live as noble savages, there is nothing to stop subsequent generations from developing technology. And if they choose not to develop it, that does not remove the possibility of malice, rage etc. They might not have battlestars to kill each other with, but they will have stones.
3) The suggestion that God will destoy Earth in the last scene is especially troublesome because it means Adama and Co. were unable to end the cycle of violence. In effect, they failed. This is strange since we have been rooting for these characters over five seasons and we find out in the last episode that their success is not final in any sense. Their attempt to achieve peace was ultimately in vain.
That being said, BSG attempted to answer as many questions as it raised, which is more than can be said for LOST.