It wasn't a bad ending, actually. I didn't know what to expect, so I was wondering if it might've been a bit of an Ego Draconis! I'm glad it wasn't. In fact I'd say it was one of the better endings I've had out of a game (up there with, say, Bioshocks 1 & 2 in that I felt that the story had reached a proper and satisfying conclusion, although not Bioshock Infinite's added ending; and then there's the worst, I think Mass Effect 3 will retain the undisputed claim to that crown for some time to come).
I don't actually mind the voice acting in BD, to be honest! Okay, the Death Knight is a bit silly but in a fairly cartoony sort of way; to look at it another way, actually I enjoyed Two Worlds, which has inadvertently become the yardstick for bad voice acting (though actually I think Skyrim's is worse: although professionally done, it's unengaging and charmless).