This reminds me, Star Wars: Revenge of the Sith. Poor Anikin got his ass handed to him and became Darth Vader as we know him. Isnt that sad, didn`t that ruin your movie experience?
What ironcreed and I said - makes room for D3.
That was a prequel though. We already know what happens to Vader so Revenge of the Sith is just a completion of that story. Even though the ending was mostly evil in Revenge of the Sith, it also did provide hope too, so people know that the story isn't over (even though most people knows what happens after that).
This game, however, doesn't offer much hope at the end. You see Lucien and your character in a crystal locked forever and Damien and his lover, Yergna (i think that's how you spell it) basically conquering Rivellon. Usually that extra cutscene at the end is supposed to foreshadow a follow up. Larian decided to squash that all together with the total evil ending. I didn't mind so much you being in a crystal, but what i didn't like was the extra cutscene at the end.