It is possible to make DRK become tank with the highest DOT

[ninninin]

You can't make all tank unique by have them shared unique feature with each other. When the time passed and the defensive kit expanded, it will eventually overlap and identity problem will return. Warrior have "Increase Max HP" "Create another Life Bar" so let that be their personal theme. PLD= Block, GNB=Evasion, DRK= Life Drain and curse because DRK is the opposite of Holy Knight and Holy Knight's usually have ability that healing self/other and blessing. Life Drain count as a magic part of The Blackest Night and it also a trait of the boy name Myste.

Tho Soul Eater and Stalwart generate less BG it is still enough to let you use 2 Salted Earth per minute when you count BG gained from blood weapon. Salted Earth will required precise timing and knowledge to make the most out of it. Having BG generated too fast would be a problem.