Good points all around, Dave. I think Cage wants the medium to move forward, but he blatantly disregards current trends in the industry or flat out refuses to admit that other types of games exist outside of violent action games and kiddie stuff. And quite frankly, his nine main points could all be argued back and forth with counterarguments that prove this isn't a cut and dry issue. He says things like, "Games need to be more adult" or, "Most games have protagonists with guns" and never acknowledges the merits of either. I'm playing Spec Ops: The Line right now, and that is a violent action game that is trying to say something about war and its effects on soldiers. While Spec Ops may not succeed at everything it tries to do (much like Heavy Rain), I'm glad it exists and I think it shows that the medium is trying to move forward. And David Cage hasn't really done enough to push the medium forward with his two titles to start telling the industry what to do. This is the equivalent of Uwe Boll telling Hollywood what to do (Okay, maybe that's a little harsh. More like JJ Abrams telling Spielberg what to do).
I will 100% agree with Cage that gamers need to vote with their wallets. This is the reason I'm not buying Dead Space 3 and I plant on buying Amnesia: A Machine for Pigs at full price in the summer.