In theory, if you decompiled a PS2 ISO into source, converted it into a Wii friendly format, and then recompiled it as a Wii ISO, some games might work sometimes, on some Wiis. Maybe.
Of course, decompiling a program is like turning gold into lead, then converting it to carbon, and finally recompiling it into a diamond.
1: Decompilers aren't perfect, period. Even for open source libraries.
2: We don't even know the native libraries used for PS2 games, and probably won't find out enough about them to even attempt this feat.
3: Conversion isn't kind. That's why ports take time, and are STILL worse than the original a lot of the time.
4: We don't have Wii compilers for anything that advanced anyway.
^Raw emulation of PS2 on Wii hardware is harder than this^
Feel like it should be done? Prove us all wrong and do it.