Definitely agree with a lot of this. Especially DRK's complete lack of value as an OT. Honestly, I would never let a DRK OT in any party composition, it's just an awful idea.

Also, I really dislike the idea of having a dedicated "magical tank." With the need to set a standard for a fight that would make it tankable by any job, you end up just having to make those fights inherently easier so that everyone can actually do it, while one tank is just left facerolling through (although DRK can't even really dominate magic heavy fights, so I guess they got around that...). If they want to differentiate tanks, they're going to have to do a lot better than which defensive value is arbitrarily chosen.