yes i have a little problem holding aggro with prot spec if dder (like shadow priest,fire  mage,des lock) dont have blessing of salvation.but i think its because of my latency problem,show as 400ms~500ms,but its actually more like 600~900ms due to the lag spike.......really fuxx up..

single mob,usually start with revenge,shield slam,sunder and so on,if i have too much rage,then queue in a hs.shieldblock every 6sec if its a boss or hard hiting mobs,otherwise  i wont use it since my Avoidance is high enough(26%dodge,16%parry,22%block unbuff)to keep revenge up.

multi mob,well..tc,cleave,tab sunder/revenge and taunt...

In heroic nor raid,i have no problem with rage generation.I usually swap in some hit rating gears for trash mob though.
if i dont have rage or my skill normal hit miss parry dodge alot,i will just taunt it and follow by a shield slam+heroic strike.

U must have sacrificed quite a bit for stam for such high avoidance.

PS - I prefer to wear more block gear w/o gimping too much stm on multi-trash mob pulls. the more u block for the more the mob hates u. And higher block gives u extra threat on ur shield slam ( 530 per block any1? ) And i dun see it alot in ppl's rotation but shield block everytimes its up!

Threat values:

I did not do the work to get these numbers and therefore I can't vouch for the accuracy or take credit for them.  link to source: http://forums.wow-europe.com/thread.html?t...=94319875&sid=1

These are before the defensive stance multiplier and defiance talent multiplier (which are additive afaik 1+.3+.15=1.45)  and BEFORE damage to get a rough idea of how much threat you're pumping out from your attacks.

Sunder Armor (Rank 6)  _________ 301
Heroic Strike (Rank 10)      _______ 196
Heroic Strike (Rank 11) [book] _____220 (guess)
Revenge (Rank 8)  _______________417
Shield Bash (Rank 4) _____________230
Shield Slam (Rank 6) _____________307
Devastate (Rank All)______________101
Thunder Clap (Rank All)___________+75%dmg
Cleave (Rank 6) _________________130 (split)
Disarm_________________________104
Mocking Blow (Rank 6) ___________290
Demoralizing Shout (Rank 7) ______ 56 (split)
Battleshout (Rank 8) _____________ 69 (split)
Commanding Shout ______________68 (split)
Hamstring (Rank 4) ______________181
Excecute (Rank All)_______________0 (nostance)
Spell Reflect  ____________________0
Piercing Howl ____________________0
Concussion Blow _________________0

Like Reis above says, swapping gear improves your versatility in 5 mans.  It was the same in vanilla wow, you really couldn't tank in 5 mans in your raid gear (well you could but it was always more efficient to tank those instances in DPS gear) because you may have already outgeared those instances.  +hit gear is great for tanking but note that it doesn't get rid of the mob's ability to block/dodge and parry your blows.

With my current level of gearing, i don't feel comfortable dps tanking as yet.  However neither am i tanking in my raid gear.  I have a nice in between set which i use for 5 mans which prioritises block value.  It uses a combination of tbc blues and lvl 60 epics and i find that the aggro i get with 550 block value shield slams far exceeds threat that can be pumped out by dpsers.  My max shield slam so far in the game is just below 2100 damage, however finding mobs with 0 armor is not realistic.  Crits of 1600 and above are not rare though.  With the innate threat value of 307 above i can get about 2.7k+ threat from a single shield slam crit.

You can tell from the threat guide above that sunder with static threat of 301 is easily outstripped by anything with innate threat+damage>300 for threat.  So really it shouldn't be the major threat generator for a protection warrior.

I personally use heroic strikes a lot.  But how much I use it depends on how much threat I need to frontload.  Innate threat above is 196 and the extra damage from HS is around the same as well at 176, resulting in 533 extra threat in addition to the threat you would have done normally from your white hit damage (also the 176 extra damage can crit!).  All well and good but you also lose out on the rage you would have gotten from the white hit, which means to cause the extra 533 or more threat you would have used more than 9/12/15 (depending on talents) rage. 

So it's really depends on whether the rage income from mob damage is sufficient to spam heroic strikes or to hold back to use your instants when you're not getting hit.  It's encounter dependant on whether you want to maximise threat per rage or threat per second.

Edit:
screenshot add,just want to prove i am not bullshiting lol

do depth wound will coz of lossing argo?

i must say i'm pretty impressed. this is mine. I can see where ur extra dodge comes from. Weapon, 2nd ring slot, t4 shoulders n hands. guessing ur bracers is from heroic ramparts chest n belt from heroic quamirran. what's ur first ring gem slot n gun.

wow latency is more accurate now. it changes more accurately so if theres no players around, pings will drop drastically.