Tank Mitigation vs Tank DPS.

[SturmChurro]

If we are talking about melds, the difference between tenacity and other melds in pure damage is just 1.6-1.8%.
As a tank you should always focus on getting highest ilvl gear, so there is not really too much of a choice if it comes to secondary stats in equipment. So you are left with melds as your choice.
A tank in raid will on average do about 60% of the damage a DPS job is able to dish out.
And average dps could do about 10k, multiply it by 4, add two times 6k, and effectively you are sitting at around 10-11% of contribution to the overall team dps in raid.
How much will a 1.6% affect the raid team dps? Wel basically 0.16%
Killing it 0.16% will virtually have zero effect on the amount of healing done to a tank, if 4% does not, then 0.16% will not be even noteciable by a parser.

Again, even if the damage increase is miniscule, it is a damage increase and benefits the party more. In a trial environment, with half decent healers, a miniscule % of increased mitigation will not help at all. A crit on a heal will make the difference, and the way heals and fights are designed in general make it even more useless. A tanks skill, and knowledge of the fight combined with smart burst, and good damage output is a better tank. All a tank needs are it's dcd's used at correct periods.