The ending was horrible I hate series ending on a cliff hanger I would hope they thought they had another season to work with. I actually enjoyed season 5 the series started to pick up for me did not enjoy season 4 for the most part.

I think that had to be a situation where they felt they had to leave it open for another season. But that just sucked. They should've had some sort of payoff for the fans that had been watching the whole series

Plus, you don't HAVE to end the season with a cliffhanger. They gambled and lost and that sucked for the fans.