There can be a lot of emulation overhead, depending on how the emulation is done. So the fact that the hardware is more powerful than the Wii doesn't mean you

There can be a lot of emulation overhead, depending on how the emulation is done. So the fact that the hardware is more powerful than the Wii doesn't mean you could successfully do a high-fidelity Wii emulator on it. It was only relatively recently that you could run a high-fidelity (bit-perfect, cycle-by-cycle actual emulation of the underlying hardware) emulator of an N64 on a PC. E.g. Project64 required a Pentium 4 with 1GB RAM and a GeForce 9000 in order to emulate a 94MHz R4300i and its vector coprocessor. (And I'm not sure how many shortcuts Project64 takes.) Anyway, it might be that the hardware is overkill because they want to use it for other platforms, or it could just be that they're doing very high-fidelity emulation and are just beating the performance problems into submission with transistors.