I would say I agree with all your points, but you are missing the most important argument for why the Xbox 360 doesn't appeal to casual gamers:
It costs too much.
Edit: to expand, I think it will do better when it's cost comes down as well. however, $200 is mass market price, not $250. It's going to be another year and a half before the 360 hits that sweet spot more than likely. The Wii has managed to bypass that mass market barrier of $200 by having a pack-in game, but it will be a while before the 360 reaches that. Remember unless they start packing a memory unit the core is still a worthless piece of crap.








