First off, I welcome any and all conversation however tangentially related to my post. I'm not a big fan of OP ownership, so take this where you like.
I game with a table of forty-somethings. We've been around the block a few times. Most of us have been gaming since the late 70s. When 4e came out we decided to give it a shot -- it's slick and sexy and we have fond memories of D&D despite spending the last several years pretty far afield.
We read it. We were impressed with the quality -- even precision -- of the design. We set some stuff up. We played it. And then we dropped it, probably forever. I am interested now in why we dropped it and am trying to take apart the experience because I'm sure there's some game designery ideas in the wreckage somewhere.
Our experience with the game was VERY combat heavy. Long chains of fights -- hugely fun, complex, tactical fights -- with a few short colour scenes here and there. We had good motivation, good purpose, and some fun characters. But it never really flew.
So the past few years we've been playing games that really emphasize characterisation and story -- Dogs in the Vineyard, Spirit of the Century, Reign, Diaspora (our sf fate hack), and the like. What I think happened is that these games, by helping build a strong and even complex sense of motivation, forced us to start building opposition that had more dimensions than just Evil. We were bumping into areas where the player characters were distinctly amoral compared to their opposition, even, and players struggled with that and characters grew and developed and sometimes became unsalvagable while others saw one proverbial Light or another.
So when we started enjoying 4e, I actually found myself feeling a little sick. I had grown used to humanising the opposition in games, and here we were murdering them unquestioned on the basis of the labels Good and Evil. I couldn't really find a way to dehumanise some of the opponents -- I mean an otyugh, sure, no problem, but the de rigeur first level opposition is frankly sympathetic. I like kobolds in 4e. Murdering them for their loot just doesn't work for me at all any more.
I'm not saying that D&D has a moral defect in it or that people that play it have one. In fact I think what our table has acquired is a defect or blind spot -- having come to love a certain kind of story with certain kinds of opposition, we just can't get our heads around the idea that a Good or Evil label is sufficient for motivation. That whole genre is (perhaps temporarily) lost to us now. It wasn't that 4e failed to engender role-playing, it's that we found ourselves uncomfortable role-playing in it. Our characters were not people we liked. They were exactly the kind of people I normally have no truck with -- people with reflexive moral assignments they are prepared to follow up with violence. But more than that, there was no hope for them to change. I could stomach a character like that who could change, I think.
I'm pretty sure there's something about the advancement system that drives this, because I know I felt a pressure to provide combat scenes in order to keep up the advancement pace. But there was also the fact that it's just fun to kill stuff with 4e. If we weren't pretending to be the killers, I think it would have been fine.