I dunno I levelled as prot, I think you just have to get used to mostly ignoring all non-elites, in brd that means, screw sundering the packs of dogs, focus on tabbing through the elites, sunder one, slam another, revenge the 3rd and just tab through the mobs using abilities that make threat. I was just charging in thunderclap switch to defensive demo shout, sunder tab sunder tab sunder tab slam tab, sunder etc etc. when you get to around incendius or the vault, the packs of mobs by there, only 1 or 2 are elite, the rest can be ignored. just let the dps nuke the non elites and just focus entirely on building threat on the elite mobs.
I actually macro'd sunder armor with this
/startattack
/cast Sunder Armor
that way, every time you use sunder it also starts auto attacking. because ofc, it doesn't if you tab to a new target it stops autoattacking or if something dies it also stops, this macro is great for making sure you are always attacking..
the only other way you can maximize your output is by using berserker rage before pulls because that makes you generate more rage = more threat. this it my onxyia/magmadar stance dance macro. because of the gcd it requires two presses to cycle to zerker and back to defensive, but its a 1 button fear avoid macro
#showcooldown berserker rage
/cast [nostance:3]Berserker Stance;Berserker Rage
/cast [nostance:2]Defensive Stance