In the latest Dragonflight Alpha Build 44999, Holy Paladin’s Rule of Law talent no longer increases Mastery. Blizzard confirmed the change is intended.

(Source)

Rule of Law no longer mentions increasing our Mastery, which seems like a significant nerf

This was an intentional change. Rule of Law provides unique utility to increase the range of your heals. The reality is, people used it as a throughput cooldown. Not every situation needs a range increase, but having the option to do so is nice and not something we wanted to remove.

I cant find magic dispel on Holy Paladin

This is something we’re working on, we don’t intend on removing the ability to dispel magic effects from Holy Paladin.