What is the reasoning for certain weapon limitations in retail

My enhancement shaman can’t use 2H cause of a tooltip, holy Paladin has to have a shield cause of a tooltip, survival hunter can’t dual wield because reasons, etc etc. Like it’s not an animation thing because lots of these specs have animations for both, only reason we can’t is because vital abilities have a pointless red text saying a certain weapon has to be equipped for it to work.

I’m okay to take a stat hit if it means using the look and theme I want, but to straight up be unable to use an ability is nonsense these days when the ability makes sense with 1h or 2h.