Well, actually, the truth is that I never really got into Four Swords. And it's easy to draw the similarity between NSMBWii and Four Swords (though the history of what Nintendo's doing here also touches Mario Galaxy, Windwaker, SuperScope, and Super Mario Bros. 3). I'm not arguing whether we'll like the game or not, because by my track record, it may turn out more likely not.
The truth is that I'm trying to explore why Nintendo may have removed online or decided never to add online to the title. Let's not forget that we're dealing with a company that has talked about trying to remove "impurities," or aku, from games, and in this case it may simply be that with New Super Mario Bros. Wii, online gameplay may have been an impurity in the experience, instead of an improvement.
There's this common train of thought that more means better, that we can add features, build a longer list, tack-on more functionality and ideas, and in the end this'll make things better. Nintendo rarely subscribes to that. Instead, it may be Nintendo's restraint in their quest to produce their titles, polished gems with few or no impurities, that make them the company they are, or always have been.
Now, that doesn't do anything to sate my appetite for the next Perfect-Dark co-op mode. Co-op is something that the other guys are doing more and more in bigger and bigger ways. But at least I believe that Nintendo is doing what they believe in, and with all their heart. Any loyalty I have for the company is grounded in that trust, not in whether I liked the last Zelda game or not. (for the record: I LOVED Phantom hourglass, but was disappointed with Twilight Princess)