Tenacity proven better? (BiS for tanks?) Gear Stat Calc

[Pells]

The 30k-ish less damage he'd take would be over a 11 min encounter, which translates to like 50 dmg taken per sec. Over a gcd (2.5s) that's only 125 less dmg taken per gcd. That's nowhere near enough to allow "extra healer dps." I'm not saying you should avoid tenacity, but saying tenacity build would increase healer dps is questionable at best, unless the "dps" BiS gear has like 2k less tenacity than the tenacity build or something.

30k damage is one heal, give or take. It's an extra gcd for the healer that isn't devoted to healing.