Well if anything I would think blurry textures would be less noticeable at a smaller resolution, as you will have less pixels to deal with. I guess it depends on what resolution the textures were made to run on, but that all just kind of depends what will be in the foreground and background, and which characters are important or not.
Most Wii games look fine as is, so I really doubt it's so much of a TV resolution problem. You also sit further from a TV than you would a computer screen, so all of those can impact perception of quality. But the bottom line is, if in fact the textures were all resaved at a lower resolution to save space, it will be noticeable anywhere.