Well as I said and another has, Zelda uniquely can look more shitty in one way or another.
If you're going with a component cable or a composite(rca) cable things change, but also the display type can make hell with it too.
I started the Wii using a Wega tv and a RCA plug and Zelda was blurry a bit, not that sharp, was really spot on for a GC title. Soon I moved up to a component cable, yet still 480i on that stupid wega and in that case the game lost the blur and was more sharp, but you could start seeing little squares in the detailing the blur masked. Shortly after that I had some xmas or b'day cash I forget but I got a 26" Panasonic Viera LCD and plugged that in with the component cable and then things got insanely crisp switched into 480p mode, but also then the textures of the game and edges of the environment also got 'grainy' looking much more noticeably than the sharpness of the 480i/Wega/component combo.
The interesting thing is, the other games I had at the time (Metal Slug, Wii Sports, Excite Truck) stuff like that they all looked crazy sharp, but the texturing didn't have any 'grain' to it at all. I believe the problem is Zelda being a GC port to a somewhat changed internally and beefier GPU unit isn't 100% compatible and as such the textures took a bit of a knock. I hated the thing on Wii as it just felt off and I took forever doing easy stuff (ending the burning cart in the field, etc) stuff so I got rid of it. Shortly after sitting on it for ages I got the GC game and sold the Wii one and restarted, and on there in GC mode on the Wii the grain vanished. I'm convinced it's just another piece of proof of shit happens when you port over stuff.