Apple fixed the major iOS 6 Wi-Fi problem quickly. That foul-up turned out to be a missing Apple Web page. While Apple siming replacing that page cured the networking headache for 90%+ of Apple iOS 6 users, other Wi-Fi problems are continuing to pop up.
A quick look through the Apple Support forums shows thousands of iOS 6 Wi-Fi problem reports. Winnowing them down, it seems there are two significant iOS 6 Wi-Fi problems left.