This has been partially covered in the topic called "Support for USB network adaptors (Feature Unavailable). To rephrase the request:
Could a setting be added in the user interface settings screen to “Disable Internal WIFI” (disable wlan0)? This would be useful if more folks buy USB WiFi dongle adaptors to improve connectivity. Some have tried it in this forum with success (wlan1 overrides wlan0 automatically) while others haven’t. This shouldn’t require rewriting lots of code to account for every different kind of adapter as suggested earlier in that topic.