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

[Fiora]

Lua is really really common in games nowadays; see here. Speed of scripting systems typically doesn't matter too much because they're what you use to control game logic, mission scripts, etc, not slow things that require a whole lot of computation. Though even Lua has a JIT available (luajit), and the language (like python) is compiled to bytecode before being run.