^ I think a lot of this is fair. Although I stipulate my ignorance about games other than D&D and BW.
The only thing I wanted to add (reiterate?) is that while that might be true -- and that the beliefs, etc. structure of BW, along with the way it treats "failures" is quite interesting -- it also carries with it a lot of baggage, to use a loaded term that expresses my assessment. This is the setting, character creation, and combat rules criticisms I referred to in my earlier posts.
So, the costs of admission to that system may be high. For some players, to whom such things are important. Or, alternately, have not had enough positive experiences with the other aspects of the system to outweigh the bad stuff, those costs may be prohibitive. This, I think, explains my thumbs up for Mouseguard and thumbs down for BW.
Further, I think this makes it a bit equivocal whether Burning Wheel qualifies as a "good" games (full stop) or an "ok" or even "passable" game with some really intriguing great elements to it. Combat, character creation, and setting are, one could reasonably argue, are things central to an RPG.
Finally, I'd say the typology implied by the above post may be pitched at such a level of abstraction to be divorced from actual experience at the table. For example, I play D&D and M&M pretty regularly, apparently b/c I love ampersands. According to Josh's typology, they are essentially the same game, and they do share very much in common. But, I find my experience as player and GM of both to be radically different. Likewise, it's hard for me to say my experience running/playing Rifts, WoD, Godlike, D&D, M&M, and Star Wars Saga Edition were all, in essence, identical. What I'm saying is that typology may be an unhelpful one, in the way that saying that Basketball and (American) Football are essentially the same game b/c they both involve balls, scoring, referees, and fouls.