Nobody really expects tanks to pull 3~3.5k DPS in dungeons. I can’t say I’ve ever encountered any individuals that advocate for tanks to tank things in their DPS stances when in dungeons or “easy mode” 8-mans/trials, or even 24-mans. And I’m closing in on the 5,000 instanced raids/duties achievement (so I’ve done A LOT of content). Because rDPS, in those instances, typically doesn’t matter, because a lot of the bosses don’t even have enrages, so there’s no need to pull 99th percentile numbers in Skalla (there are exceptions with some of the 24-man bosses though, and the 8-man bosses do have enrages, though the check is way more lenient than in Savage/Ex).
Only in Savage and Ex trials will you find people pushing for tanks to really drop their stance, and focus on contributing to the rDPS. But, again, I’ve rarely encountered anyone who tells the MT to drop their stance and start tanking in DPS stance. It’s anecdotal, of course, but I really cannot recall ever seeing anyone complain about this outside of a static setting. In those settings, it comes from the group wanting everyone to put forth as much effort as they can to kill the boss faster, meet checks, and/or push their jobs to the limit.
Personally speaking, I don’t tank much, but when I do, I drop stance. Because there isn’t much reason outside of mass pulls in dungeons to have your stance on—purely because the bosses typically don’t hit hard enough to warrant it. Proper management of your enmity, the DPS’ enmity, and proper provoke/shirking from your co-tank provide that you should never lose aggro, so why not throw out some extra damage while you’re at it? I don’t expect every tank to do it, and, again, I rarely see other people call out other tanks for “tanking in Shield” or “tanking in Defiance” the “entire time” of a raid.
Most hardcore raiders really don’t care what tanks do in dungeons or even 8-mans or 24-mans. They only care about what the tanks in their statics do. Sure, there are twats out there that consider themselves “hardcore”, but I feel like most serious raiders really don’t care.