Tanking in WOW used to be about dpsing. That is, much of the time the job of the tank was to push the threat ceiling as high as possible so that the actual dpsers could deliver maximum damage without having to throttle themselves. When a tank was hitting buttons most of those buttons had nothing to do with being tough but were generally there to enable damage. Those buttons that were about being tough were usually just hit on cooldown with no thought required. If Holy Shield is available, you hit it! Tanks did have to worry about not dying but most of that was relegated to gearing - once you have gemmed Stamina in every socket to maximize your HP it was up to the healers to keep you going.
Tanking these days in WOW is different and I like the change a lot. My gearing has very little to do with being tougher and has a lot to do with improving my mitigation and healing buttons. I am tougher than other folks but not nearly as much tougher as back in the early days. The damage prevention focus has shifted from gearing to playing and I like that change a lot. I have a lot of choice in which buttons I use and when I use them as I have a range of cooldowns and heals at my disposal. It used to be that a really well geared tank could be completely clueless and it wouldn't matter much for many of the fights - once you pick up the mob the healers handle the rest. Now though my play has a massive impact on how much damage I take. Dropping my 33% mitigation cooldown just when the huge hit is coming is crucial, and knowing when to do a big heal instead of mitigation is important. What it comes down to is that my gearing will not save me from the monsters but my skill can.
Part of this change is ability design and part of it is monster design. I appreciate how they have made monsters cast big damage abilities on random intervals to keep tanks on their toes. I have to know which abilities I should use specific cooldowns for and make sure I manage my holy power and other buffs to deal with them properly. If monsters just stood there and autoattacked for a ton of damage there really isn't much a tank could do but their abilities feel very much designed to force tanks to plan ahead and react effectively.
Instead of feeling like a part of the dps team I now feel like I am part of the defence team. The new massive bonuses to tank threat mean that my job is to mitigate damage rather than worry about losing aggro so I really am focusing on being as tough as possible and using my skill to defend my team instead of using it to kill the monsters. I can see how that is more of a value judgement because some people probably like the old way but for me the sense that I am using my talents to get tough feels much more appropriate for tanking.
The problem is that although I do like tanking a lot now I am way behind the curve on gear. I am slowly assembling a decent set but you really don't want your main tank to be the drastically undergeared one. Skill is important, but some of the bosses just stand there and lay into the tanks like crazy and you need a certain gear level to deal with that. I am certainly good enough for casual raiding but actually main tanking for a guild at this point would be difficult at best.
Of course I have no idea where I would get the time needed to be a main tank again, but the desire is certainly building!