Although it can ve a pain in the rear but try backing up your data and performing a restore to factory defaults, I had a couple of issues after the update to 4.4.2 but the reset seems to have fixed them and also sped the tablet up ( but that could due to having less cap installed now)
I have had the same problems with my wifi numerous times, where the note would not recognize the wifi, but all my other devices would.
This may seems to be a strange solution, but turning the wifi on and of, numerous times(lets say 30), seems to make it visible again. Also, after some time(4-5 month) it reverts back to not recognizing the device. This solution has worked for me each of 3-4 times it has happened