It is something that originated with MMOs
Tanking, in the sense of misdirection and causing your enemy to focus on one thing at the expense of awareness of another, is an integral part of both tactics and strategy as taught by almost every military in the real world.
If you redefine tanking, by taking another sense than how the gameplay mechanics of what is called tanking in games deal with it, which is the meaning of tanking that people discuss when they discuss tanking in games, then sure, you can find it to have been relevant throughout history.
But why on earth would you do that?
If one were to argue that way, then I could easily claim that the game already has perfect tanking, on the grounds that enemies do not like to leave attack of opportunity zones (you are causing the enemy to focus on one thing, namely the danger of attacks of opportunity) over others, and that melee enemies don't like to attack characters with stench (thus providing olfactory misdirection).
Of course, making such a claim would have roughly nothing in common with
either misdirection or causing enemies to focus on one thing over another, in the tactical and strategic sense you know from real-world military examples,
or with tanking in the classic MMO sense of "get all the mobs to concentrate on attacking the least dangerous rather than more dangerous enemies in plain sight, even when the more dangerous enemies are clearly demonstrating that they are more dangerous by killing the mobs such that you'd have to be a moron not to switch target" - and hence I won't make that claim, because that would be terribly silly. :p
That nitpick aside, I get what you mean, but you really don't think blocking is valuable in D:OS? It doesn't seem that status effects can trigger on blocked attacks, which - at least until late game when you're just immune to everything - seems pretty handy to me.
Tradeoff: More combat turns with lesser chance of status effects vs. fewer combat turns with greater chance.
I think it is valuable - I first started the game with a sword and board warrior and liked what I saw. It is just that when I compared the performance of my sword & board with Madora as 2H warrior, I was very unimpressed, so when for other reasons I restarted on hard difficulty around level 10, I decided to go with 2x2H rather than 1H/S+2H, and I haven't regretted it yet. Sure, there's only one Whirlwind in the game, which makes me sad, but with two buffed 2H warriors as primary damagedealers with mage backup for healing, wildfire, oath of desecration, and battlefield control + damage spells to spend on AP not dedicated to the primary melee buffing, fights are generally very, very, short.
If healing spells were weaker or healing potions only available in severely limited quantities rather than being trivial to acquire large numbers of, then I'd consider 1H/S much more worthwhile in the game. 1H/S isn't bad - it is just that the circumstances under which it is more useful than 2H don't arise often, and everybody can (and WILL if they are CRPG veterans) pick up extra gear so they can switch to 1H/S (with +shield buffs for gear) if the situation seems to warrant it.
