All addons that used to handle spec-specific keybindings died with the purge, so I decided to write my own.
I made a small addon called SpecBinding.
It automatically saves and applies your keybindings per specialization, using Blizzard’s default keybinding UI.
Switch specs → correct bindings are instantly active. No setup, no config UI, just works in the background.
Character-specific & spec-specific bindings
Combat-safe
Lightweight, native feel
No overrides, no hacks
If you’re tired of redoing keybinds when switching specs, give it a try.
Feedback is welcome 
www.curseforge com/wow/addons/specbindings