Ron Moore committed to a happy ending for BSG in Season 3

The supposed hints that BSG might not have a happy ending are a total
smokescreen, because Ron Moore committed to a happy ending back in
Season 3 when he had Helo stop the fleet from infecting the rest of
the Cylons with the deadly virus.  The Colonials could have won and
have been free the spend the next several thousand years at their
leisure looking for Earth, similar to have Cavil said that if the
Cylons just destroyed Galactica, the Cylons would be free to search
for Earth for thousands of years if needed without Colonial
interference.

A not-happy ending doesn't make an artistic triumph, it simply
advocates genocide as the solution to current world problems.  While
someone in mainstream Western television advocating genocide would
actually be somewhat artistically different and challenging, that is
not what Ron Moore is trying to say.

No, the ending will be some kind of reconciliation between Colonial
and Cylon where both are still alive and somehow have to work
together.  And it has to be better than the scenario where one side
unconditionally wins and is free from the other.