Ive been using this and its pretty neat.
According to fight club discord, the ideal CPM (cast per minute) ratio of skills as dprot is roughly:
Shield Slam - 10
Revenge - 10
Sunder Armor - 20
Heroic Strike - 10-20 (depending on wpn speed and rage)
So I made a macro to emulate the double amount of Sunder to the higher priority skills, and got very close to the ideal CPM.
Heroic Strike is manually queued with Alt. You dont want to use it unless everything else is on cd and the gcd is down (ie; Sunder is on gcd), and only if you have a surplus of rage, say over a third to half of your rage bar. You never want your HS to eat into your higher priority skills.
Shield Block is Ctrl, but again, use very sparingly. I dont block more than 2-3 times a fight, usually just to get a Revenge proc if one isnt up. Sometimes you should block more often depending on the encounter, like Onyxia fire breath, but generally block is unnecessary much like stacking defense is a meme.
Try to make a threat set, having as much crit as you can to generate extra threat.
Im using this build (14/5/32) for raids and its working out nicely:
Run this at between 30-50 ms.