Wouldn't it be a cost-cutting measure to simply to make it region-free anyway? Especially if they want to sell it inexpensively?
If they want to keep the DVD-playing part specific to regions, they could keep that limitation on the DVD dongle or whatever extension you need for DVD playback. The Wii itself could very well go without that.
I don't see much point to limiting to particular regions, honestly. I'm sure there's some reason that I could look up on Wikipedia but when many people have region-free DVD players and region-free DVDs, and can easily mod their game systems or find workarounds to that, it really seems like a moot point.
Anyway, as Australia speaks English, you'd think they could get games at the same time as North America. But then again Canadian packaging requires French as well...does American packaging require Spanish?