I've recently been revisiting the 2007 Flash Gordon
series, which was a much better show than most people think
; its first half-dozenish episodes were so weak that it hemorrhaged viewers quickly, so few people stayed around to see how much it improved in the last 2/3 of the season, and thus it had no hope of renewal. But its finale, while it had cliffhanger elements, was in many ways a perfect ending. It wrapped up the season's arcs quite nicely and showed the beginning of a status quo which was essentially what fans (all 17 of us) had wanted for the series all along.
I agree with the io9 article about the V
revival's finale being a perfect ending. Sure, it represents total victory for the villains and defeat for the heroes; but the heroes had been thoroughly incompetent and unpleasant throughout, while the main villain Anna had earned her victory through her cunning, her dedication, and the loyalty she inspired in her people. So honestly she deserved to win much more than the "heroes" did.
Also, not quite the same thing, but for a while Farscape's season 4 finale did have to function as the series finale. And what an awful place to leave off.
I thought it would've been a perfectly appropriate ending. I mean, Farscape
was never conventional and always thoroughly weird and wild. It would've been entirely fitting for the series to end with a shocking, frustrating twist that left no doubt that the characters' crazy adventures would continue indefinitely.