I'm in the same boat. Note 2 with cracked screen came back from Samsung warranty repair with 4.3 OTA software and locked bootloader. Even with root, the best solution I've found is FoxFi, which is an $8 app. Can't speak to how stable it is, I've only used it for a few hours.
I definitely miss using Wifi Tether Treve Mod with 4.1.2. No way would I have taken the OTA, but cracked screens happen... Probably time to sell this thing. At least the Note 3 despite it's locked bootloader currently can be used with safestrap which allows for free tethering solutions / custom roms.