That would be fantastic, but I'm not holding my breath.

Largely, it'll depend on how much of a contribution the gems actually make to the relevant stats. If a tank can go from 75k to 100k health by stacking stam gems, then I bet the practice will continue, especially if that difference results in the loss of, say, 5% avoidance/mitigation.

I caught on to that just a few months ago. I'm a bear, and was walking around in ICC (months ago) with over 70k health. But I was working hard to hold aggro, and tanking was a miserable job. I (and the other 9) lived and died around me constantly taunting back stray mobs, stray bosses, hell i couldn't hold a stray cat. Marrowgar and Lady D can both one shot clothies. It's embarrassing to have Saurfang pulled off of you. Slowly it began to occur to me that I'm not a tank; I'm a bear.

Agility is my stat. Not defense or dodge; certainly not parry or block. I began needing on "DPS" gear - Agil & Stam + (crit, ap, haste, expertise, armorpen). Of course the leather is already like that, which was another clue in my reorientation. So I (re)bought the melee dps ring from ICC, the dps frost cloak and so on. The only tank item i have remaining is that frost key trinket that gives 228 stam. (that's too much stam bang for the buck to give up.)

Oh, and about your comment; gems. I started putting the gems they wanted me to have. Namely agility in red sockets and haste in yellows. Now, to me, the point of putting gems in sockets is to get the socket bonus. Lets me know I'm doing it "right". Blues still get stamina (obviously more health is better as a tank), but feral leather doesn't have blue sockets. Yet another clue from Blizzard.

Also replaced the survival instincts glyph for mangle. Now when I hit it, I've only got 75kish health instead of 90 or whatever. That has not once ever made the difference in wiping in ICC. 20 seconds of 15k health won't save us, but extra threat to keep them off the healer just might. Blizz never intended for you to need 70k to tank ICC. They did intend for tanks to hold aggro in there though.

So after all that, health was more like 62-65kish, and armor is down a tiny bit too (the cloak and rings had armor, but more agil gives armor) 30k?. However, dodge is over 50%, crit is at 60%, and dps increased over 3 fold; from about 1.5k to 4kish dps. I very often saw 6k dps in ICC with the buffs. Threat, obviously, off the charts. Insane. I simply can't be off tank on a single boss fight. I will pull him if I do my full rotation. In VoA and Saurfang where you're bouncing him back and forth, I have to back off so the other tank keeps him. It took getting a few 10 stacks from Festergut to teach me to swallow pride and do what the raid needs.

Anyway, now I have the easiest job in the raid - main tank. (well except nobody's raiding nowadays) By far easier than trying to find a damn spore, or kiting Saurfang's minion things, or getting out of Marrowgar's way. (Heh, when I became a real bear, I began chasing Marrowgar during bone storms. It's what a bear would do. rah.) Also, I didn't have the trouble other tanks had in this latest patch. I can't spam swipe anymore, I have to time it well. Otherwise, not much change for me, except even more health. Heh.

I balanced my character in tune with the way the devs balanced the game. To your point, I also used the gems they intended. I became much more powerful in doing so. That's a bear's perspective, I never played another tank.

That's what I did with my pally for Heroics too. Keeping agro was impossible in PuGs and Mages and Locks doing so much burst. So I dumped all my tank gear, grabbed a Wrathful 1 hander and a shield and threw on my Ret gear.
I only have 38k HP unbuffed now but everything is a lot smoother as healers have no problem keeping me up and the DPS aren't having to stand around doing nothing to keep from pulling agro. At 85 and in raids it'd be different, but it works well at 80 for JP farming.