I thought I was watching a rerun of Ashes to Ashes - IT WAS THE *EXACT SAME* ENDING.
BSG may well have been a cop out, but it was within the theme of the show. Since when did dying souls need to jump through time and blow up a nuke? Seriously, why? For me this is the biggest televisual kick in the nuts - ever.
Only the side-flashes were the after-life. The rest was regular life, it was basically a big flash forward.