Probably already been said, but I just wanted to comment that I, too, feel more games need better/happy endings. I'm so sick of them making great games and then leaving it off with the idea for a sequal that will NEVER come. Yes, I'm looking at you, Beyond Good & Evil, just like Yahtzee is.
But more to the point, I'm sick of games that actually DO end on good notes, and then turn around and practically rape the main character and kill everyone they love in the sequal JUST so you can make a sequal. Actually, that's a really stupid way to start a storyline/series, too.