Yes! I know Jared and Jensen have both already expressed willingness to come back for more someday in the future, which I think bodes well for the finale. It seems unlikely they'd be saying that if there was a real shut-the-book type of ending.

P.S. I meant to say in my first comment that Reapers ARE angels, and that's a very interesting idea that any angel who died could be the next Death! They'd said in the past that only the next Reaper who dies becomes the new one, but who knows how Jack might choose to tweak things and open it up to any angel. I could see Anael being kind of a cool Death...