I'm going to start out by saying that I like Malstrom, and I think he is one of the few who actually understand Nintendo's business strategy. However, the more I read about his specific game criticism, the more I think he is just trying to bend his theory to his own personal taste in games.
When Malstrom says 'content', he does not mean it in the same sense as the average gamer. The average gamer sees content as how many levels there are, how longer are the levels, how many characters there are, how many weapons there are, and so on. This is not what Malstrom means. He has used the word 'mythos' to describe the same thing he is talking about here.
King Kong is the mythos behind or content of Donkey Kong.
Alice in Wonder Land is the mythos behind or content of Super Mario Bros.
Malstrom's argument is that games with great new content are well received by gamers, and therefore sell better. Let's examine that a little closer.
I'm going to skip the two arcade games he mentions because I'm not old enough to know much about them, and we don't have data on them either.
Super Mario Bros. is praised by Malstrom has having great new content. It sold 40.24 million units worldwide, 6.81 million in Japan, 29.52 million in America, and 3.91 million in Others. It was a great success, although bundling pushed these numbers higher.
Super Mario Bros. 2 in Japan (or Lost Levels as it is known in America) is criticized by Malstrom for having no new content. I agree with that. It is basically the same game on hard mode. It sold 2.65 million in Japan. It was not released anywhere else.
Super Mario Bros. 2 in America is praised by Malstrom for being great new content. It sold 7.46 million worldwide, 0.7 million in Japan, 5.47 million in America, and 1.29 million in Others. The reason it sold so poorly in Japan was because it was released in 1992, four years after the release of Super Mario Bros. 3. But for all the praise that he gives this game, Malstrom does nothing to say why it sold so poorly in the other two regions compared to SMB. I think this is the first example of Malstrom trying to force his theory to fit his own personal taste.
Super Mario Bros. 3 is also praised by Malstrom for being great new content. In fact he calls it 'the zenith of Mario content'. In other posts, he also makes it clear that this is the best, most content rich Mario game. It sold 17.28 million worldwide, 3.84 million in Japan, 9.69 million in America, and 3.75 million in Others. If this is the best, most content rich Mario game, why does it outsell SMB 2 Japan (a game with no new content) by only 1.19 million units in Japan? That doesn't seem like that much. Again, I see this as Malstrom forcing his theory to fit his own personal taste. It misses SMB by almost 3 million units in Japan and almost 20 million units in America. Bundling is part of the reason, but those still seem like big gaps to me. This could be more of Malstrom's personal taste instead of objective theory.
Super Mario World is next. Malstrom says it has some nice surprises, but is missing the magic of the other games. It sold 20.61 million worldwide, 3.55 million in Japan, 12.97 million in America, and 4.09 million in Others. So, how does a game that is missing the magic do as well or better than SMB 3? Part of the reason is bundles, but it wasn't bundled in Japan where it only sold a quarter of a million less. I see more personal preference over theory here. Malstorm states that 'Mario Madness' ended shortly after this game was released. I think it just ended for him. Malstrom admits here ( http://seanmalstrom.wordpress.com/2009/06/14/email-of-mario-and-of-mythos/ ) that he fell out of gaming shortly after 1992 (this game released in late 1991 in America).
Malstrom criticizes Super Mario World 2: Yoshi's Island heavily. He blames it for killing 'Mario Madness'. Again, I think it just died for him. In the link above he also criticizes it for making Mario uncool. I would blame the marketing of Sega and Sony during this time period. Other things that hurt this game's sales was the fact that the first PlayStation had just launched, and the N64 and Super Mario 64 were just around the corner. This game sold 4.12 million worldwide, 1.77 million in Japan, 1.68 million in America, and 0.68 million in Others.
Malstrom praises Super Mario 64 for it's new content. It sold 11.89 million worldwide, 1.92 million in Japan, 6.87 million in America, and 3.10 million in Others. This game barely outsold SMW 2 in Japan, a game that Malstrom heavily criticized. Again, I see more personal preference than theory in his analysis.
Malstrom criticizes Super Mario Sunshine. It didn't sell too well for Mario. It sold 6.28 worldwide, 0.87 in Japan, 4.03 in America, and 1.38 million in Others.
Malstrom also criticizes Super Mario Galaxy. He makes some strange claims without proof like 2D Mario fans bought the game because of no alternative, and people think that Petey the Piranha and Bowser Jr. are annoying. This game sold 8.07 million worldwide, 1.05 million in Japan, 4.20 million in America, and 2.82 million in Others. He has a right to wonder why this game didn't sell more than it did, but his criticism seems superficial here.
Malstrom ends by criticizing New Super Mario Bros. He makes the claim that many fans thought it was disappointing. Proof? I've heard pretty much nothing but praise for this game. Critics didn't think it was disappointing. It is the sixth highest rated game on the DS, and only misses the top spot by less than 4 points on a 100 point scale. This game sold 19.22 million worldwide, 5.69 million in Japan, 7.08 million in America, and 6.45 million in Others. Malstrom claims that this game sold so much because it was selling to people who never played SMB, so it was like playing that game for the first time. It could be true, but again, there is no proof of this, so it is hard to tell. I think his personal dislike has clouded his theory here again. He should be trying to explain why this game sold so well, not trying to cut it down and say it lacks content. He is contradicting his own theory here.
Short version/Conclusion:
Malstrom has warped his 'content' theory to try and fit his personal taste in games. When actually looking at the sales of these games, his theory falls apart. Properly applied, his theory might have merit, but that is yet to be seen.