The Wii has a limited CPU (750MHz only) nothing comparable to your PC
Browsing files inside an archive may be very slow, especially when entering a large archive.
Decompressing a file while playing it will slow down mplayer, possibly leading to framedrop (which isn’t activated by default afaik)
Anyway I am interrested by this idea and will submit a patch at some point.
Hope the team will like it <3
They’re picky when we suck their CPU cycles 😉