Wow glyph of intimidating shout
Determining when and how many to use depends on a number of factors from fight mechanics to how much mana your healers have left, making it a sometimes difficult and important personal judgement call.
In smaller 5-man situations cooldowns make things easier on healers, but are generally not mandatory, whereas in raid settings there are mechanics that demand the tank use his cooldowns or die.
Proper use of cooldowns requires anticipation of, or quick reaction to damage levels that your healers can’t keep up with or are incapable of handling at that moment due to being dead, mind controlled, etc.
Generally speaking if you feel threatened it’s better to blow a cooldown or two rather than potentially die, because if you do die your team will more likely than not follow soon after. Threat is somewhat easier to manage since patch 4.3, as all of your abilities now add more threat, so Sunder Armor’s threat generation is less essential.
Keep in mind that Devastate adds the Sunder effect and that other classes also offer the effect: With the changes to threat in patch 4.3 (everything you do generates more threat than before) it becomes less necessary to focus on generating threat (an this is why Hit, Expertise, and Crit are devalued) and allows more emphasis on mitigation (survival.) With that in mind, your recommended stat priority becomes: and your other abilities should be more than enough to maintain threat.
Mastery – Critical Block: Protection Warrior Mastery increases the chance to block as well as critically block, making it the most effective secondary stat for survivability.
Your should be enough and generating threat should no longer be an issue. When reforging gear, it’s important that you look to reforge from your least effective stat into the most effective for whatever gear goal you are currently aiming for.
Otherwise your single target rotation remains pretty much the same except for using Revenge before Shield Slam when possible.
As a tank, your cooldowns largely relate to your own survival.
In response to druid's complaints, Blizzard added a clause to Glyph of the Stag that gives you a separate spell for Flight Form, in order to activate Travel Form wherever you want.
But glyphing the ability means you have to be a stag rather than a cheetah, and it also turns you into a mount for other players.