From one tank to other tanks..STR Gear is not a thing anymore..Get used to it now!

[Klongol]

Because the people who've done the maths came out with a figure of 3-5% mitigation for every 1,000 tenacity. A full set of Lv320 fending accessories plus melds yields something in the region of 400 tenacity.

So, if we assume the higher end, Tenacity provide the following boost of 5% per 1k: 5% reduction in ALL damage (magic or otherwise), 5% increase in ALL damage done, and a 5% increase in ALL healing received.

Add in melds to both left and right side for tenacity and you're easily exceeding 2k Tenacity total. On top of this, you keep your 25% larger HP pool

I don't think I'd call a 10% adjustment to ALL 3 areas to be a miniscule bonus. Hell, I'd argue that taking these increases far outweighs the, at most, 15% increase in DPS a tank does with STR accessories.