This posting is older than 6 months and can contain outdated information.
Thanks for asking.
What you are seeing is this:
1) due to the way the Wii Remote supports Bluetooth, the Wii Remote needs to be constantly searched for over Bluetooth in order to automatically establish a connection when the buttons 1+2 are pressed. This means Bluetooth traffic even if the Wii Remote is not connected. In contrast, other Bluetooth remotes like the Sony PS3 BD Remote can establish the connection by themselves and don't need or cause any Bluetooth traffic when not connected.
2) Bluetooth and WiFi (except 802.11n - which operates at 5 GHz) use the same 2.4 GHz frequency range. So they'll naturally interfere. In most cases, they only do to a minimal extent, but in same cases - and that seems to be yours as well - they do a lot. This is a physical phenomen that can't be solved in software. You can work around it by using a 802.11n Wi-Fi network on the 5 GHz range, so the two can't interfere with one another. For more information on Bluetooth, Wi-Fi and which frequencies they use, please see the detailed explanations of the technologies at
http://www.iospirit.com/products/remotebuddy/hardware/
You can find the same information in Wikipedia, Apple's Support Knowledge Base, etc.
Best regards,
Felix Schwarz