Tales of Symphonia doesn't support 480p anyway. So it'll always run in the default resolution regardless of component or composite cable, pressing the B button or any Wii settings.
That game in particular tends to look blurry. It's part of the way the graphics engine of the game was done. You'll notice that in some scenes some characters are more or less blurry than others depending on how deep in the 3D field they are in. It's not something you can work around.
And just FYI for everyone, the component output (that supports 480p) was only available in the US for a limited time as well. Newer revisions of the Gamecube in the US also only had composite cables (480i only). They dropped it pretty quick if memory serves. Nintendo says that it's because only a small percent of their user base actually took advantage of the feature, so they cut it out to save production costs in later revisions. Not sure if PAL versions ever got progressive scan.