It is quite refreshing to have a professional point of view on this matter. I liked the post quite a lot, as a fellow RPG player.

Of course, I believe a lot of elements factor in when we discuss about what's "fun" in a RPG session. I guess, as a player, I agree with your conclusions about fudging dice rolls (I know one of the GMs I've played with has done it during our first adventure, but it was justifiable since we were playing in a ruthless setting and most of the players were new at the experience). But a lot can be told about the players themselves, sometimes doing stupid stuff in the game can result in having a lot of fun but ultimately breaking the immersion, sometimes there's too many "shy" players and they end up having no contribution to the game (and therefore, no fun, because I firmly believe that winning by merit of someone else is not really fun to begin with). Rules can get in the way of the experience if the GM is not really capable of including them seamlessly in the session, I think, but they are the basis for every game out there.