Not really, actually. The Zelda games, despite their timeline connections and overarching plot, world and themes, are mainly self-contained experiences. For the most part, the game are really meant to be enjoyed on their own. There was never a Zelda game made that actually REQUIRED you having played a previous one to understand what's going on, even the ones that heavily reference previous games like The Wind Waker or its own sequels.
Because of this, it automatically means being canonical is just slightly different than it would be with another series. While obviously, talking about it literally, the definition is the same, you still come to the fact that the games are enjoyable regardless of how they connect to the others.
So I think it's pretty irrelevant if the manga are canonical or not. They're still fun, as are the games, so it doesn't really matter and causes no harm as-is. Two other reasons though, for good measure. First is the fact that BECAUSE the games are fairly stand-alone, adding more to them through a manga wouldn't make sense, as it would change that. Second is that if new manga were made that WERE canonical, it would make the endless chore of telling people that the manga aren't canonical even more irritating because then there
would be some canonical ones.
Actually Valexia, it is the other way around. Western Comics are the silly ones.
That's really open to debate and probably shouldn't be something we get into too much. Besides, neither of you are making very clear what Western comics and what Manga you are referring to, as they are very different. The Manga, Nausicaa is an incredibly mature, deep, and beautiful story, whereas Ceres is a teen romance with no intellectual value, just some fun. The same two examples could be replicated in Western comics. Let's try Watchmen versus Dilbert... or even Deadpool, much as I love him. See my point?