Is it actually possible to just rewrite a GCN/Wii game into a PC game?

[Benze]

You would require the sourcecode of the game and recompile for your target architecture (PCs are usually x86, phones use mostly ARM etc.). With only the ISO this is not possible as far as i know. You can not get the source code from that. You would have to rewrite the entire game and use some serious reverse engineering.