Bluetooth is just a wireless communication layer, like 802.11a/b/g/n are. There are a few pre-defined protocols that are supported(L2CAP is likely the one used in this case, with RFCOMM being runner up, and with BNEP and OBEX being the most common), but what is spoken using those is the 'magic bits'. Just because the remote is a bluetooth device, doesn't mean it has to speak some magic common language that all bluetooth devices agree on.
Think of bluetooth as the HDMI cable between your PS3 and your AVR. Bluetooth really only requires that the devices be able to detect that the other is there. There's no requirement that they be able to work with each other in any guaranteed way. Now with HDMI being a much more targeted spec, odds are VERY VERY high that 2 devices talking to each other over HDMI will be able to work together. Bluetooth, in contrast, is a very generic spec.
Anyways, where I was going with that...
The wii may use bluetooth, and the ps3 may use bluetooth, and both may have similar features, the only thing that their bluetooth implementations likely have in common are what they're used for.