I find it hard to imagine that Krieg is NOT a tank. His passives are the same as Sieg's. He has the same HP increase skill as Sieg (100 hp at start, 80 per level) and he gets minimize the damage like Sieg. I'm sure his durability is up there with Sieg's (it still boggles me why people say Tia isn't durable. Sure, she isn't as durable as Sieg, but she still withstands a crapload more than Dainn, Eir, and probably Dacy, assuming equipment is the same. Really, the only thing that REALLY differentiates base non-equipment character HP at the higher levels is the HP Increase skill).
Unless you mean he isn't a tank because he doesn't have provoke or something.
I also find it hard to believe that his attacks are slow. Because he dual-wields. There isn't a single game in existance where a dual wielder's attack is slower than everyone else's. It's almost always near the upper end of attack speed. A slow dual wielder would get rid of the point of dual wielding.
Also, is Krieg officially a paladin? All this time I was under the impression that he was a monk. His backstory implies he's a wanderer and doesn't mention him belonging to a church, and what kind of paladin dual wields wooden hammers (paladins in most games usually wield metallic blunt weapons if using blunt, and almost never dual-wield) and goes bare-chested instead of in a full suit of armour?
Currently I'm main-ing two full-time fisher-girls. They fish. A lot.