The best artists are very rarely the best critics. Bergman's into Spielberg and Soderbergh, while openly slating both Antonioni and Godard.
I'm actually more suprised with Wild Strawberries and Persona on that list, the former being really quite light and whimsical, the latter being pointedly obvious, neither are close to being Bergman's strongest.
But then you're right, strip it down and Seven Samurai's just an action film, like a lot of Akira really, one of the most over-rated film-makers ever to exist. It is my fave of his though.