You're confusing this with WoW.

I spent many an hour tanking in WoW on my bear (a few world number one world of log entries) or in other game, often as a dex-based tank with quarterstaves and double-bladed lightsabers. Because in those games, they had a role designated as tank... but D:OS does not.

There is no aggro management, there is no threat, there are only 2 things in combat you need to concern yourself with in D:OS - Damage, and Control.

Characters can spend their turn performing one of those two actions - either they dish out some damage, or they control the board. Tanking, were it present, would be a form of control... but it's not. Str-based characters have the worst levels of board control and are compensated with a couple of things:

1. 2h str characters dish out the highest levels of consistant damage. Spellcasters often claim to be higher and sometimes it's true, but really a Str char will put out more damage themselves. What they won't do is put out the damage while also stunning six mobs or setting eight mobs on fire, not unless their weapon is really amazing ha!
2. Man-at-arms users get access to some pretty awesome talents, most notably Weather the Storm. Weather the Storm grants 10%*Arms level to all resistances, making it possible to stack 100% resists on them so they're immune to that kind of damage (105% and they actually gain health from it!).
They also have Picture of Health for 5%*Arms as bonus health.
3. Str users only need to invest in 1 skill to get access to their skills, unlike Dex who need 2 and Int who can have up to 5. This saves them points for places such as 2h skill adding 50% more damage. So they can use their skill points for other uses, like resisting stun. Something a caster would struggle with.
4. Finally, there exists weaponry and armor designed for lower strength players such as 1h weapons/shields or scale armor instead of plate. With this in mind ,you can take your Str guy and mix in some int magic like witchcraft to give 50% more damage, or pyro to take a haste buff. But what you can't do is make a tank char like in MMOs, because there is no threat generation/taunt function.

Good luck shifting your perspectives because you wont enjoy the game until you do, you'll just get frustrated you can't make a prot warrior like you can in games which are nothing like this in the slightest but have RPG in their description confusing you into believing they are.