Feb 16th 2008 5:36PM You're so wrong it's unbelieveable.
Any new tank should always stack stamina over avoidance. Avoidance is not good enough to sacrifice alot of stamina for UNTIL your parry+miss+dodge chance is over 102.4%. If you have 102.3% chance, you WILL every once in a while take 3-4 hard hits in a row and that will kill you, if you neglect stamina.
However, if you start stacking stamina from day 1, you will often take streaks of 4 hits, but you have healers for that. Every boss encounter in this game only does damage that you can heal through. There is no boss in Zul'Aman or Karazhan dealing more damage per second than 3 healers to heal through, and there is no boss in Gruul, Mag and up to BT dealing too much damage per second than 7-8 healers can heal through. The dangerous damage is bursts. The limit is the tanks hp, how much damage can he take before he is dead? Look at Prince. He hits fairly weak, 2k-2.5k each hit debuffed with demo shout (which should always be up along with thunder clap). This is easy to heal through. The danger comes in phase 2, where he gains thrash and starts dual wielding. If you get one of your attacks parried in conjunction to a thrash, you can be looking at a 2.5k, 2.5k, 4k, 4k burst, with 2 crushings, or even higher. That togheter is 13k, and he has more burst potential, reports state that bursts of 16-17k has been experienced. This may occur even if you have 40% dodge and 40% parry. However, with 18k hp, this is negated. With 18k hp, you will take the hits, go down to 1k hp (in case of a 17k burst), then your healers will quickly have you back up again (unless he thrashes you again, but I'm not sure that can even happen).
Avoidance is a nice thing to reduce the damage you take in the long run, but it is never reliable. Use stamina when you are progressing on new bosses, and replace with expertise, hit and block value when farming content, for added threat and hence your dps can nuke freely and get the bosses down quicker.