Tanking since the start of Burning Crusade now and I have to say that each addon had its up and downsides.
I experienced the famous Shattered Halls Heroic everyone talks about where you really had to take care of where your next Devastate or Shieldslam has to land or where Shield Block Value was actually a thing.
I kept playing my Warrior through WOTLK and must say that when the time of overgearing came in ICC i had to adjust my gear not in favor of Vengeance but to keep hitting buttons at all. I remember sitting down at marrowgar since I didnt gain rage at all. It felt awesome when doing 5man heroics with parts of the gear switched to offgear though.
Since then I felt kinda trapped in a downward spiral beginning with Cataclysm where prot warrior tanking just felt shit and MoP where it just felt like facerolling.
Even though a prot warrior in WoD isnt the best self-healing tank available it feels like you just have to mitigate not the boss mechanics but the slacking attention of others not noticing spikes or just enjoying to be overgeared.
I really hope (what i've seen from watching videos) that the changes Legion brings makes the tanking job a bit more difficult where I can focus on my own role and dont have to try to get my selfheal done and have to compensate another slacking dd.
Regarding the taunt thematic I have to admit that I'm rarely using taunt at all - the way threat works on live it is simply not necessary at all.
I hope my english was not too bad, thanks for sharing your Legion thoughts!