I would seriously question a decision to put non tanking stats on tank gear ie Int or Pie. Giving DRK its own gear set would be pretty dumb, from a loot standpoint.
That being said Yoshi did mention a redesign of loot drops from coil. I have a strong suspicion that they are moving towards a token drop system like in WoW. (refering to high lvl gear drops) By adding 3 additional classes, they will be randomzing useable drops in a raid way too much.

But since they have already stated that the gear system is changing, there are no rules as to what kind of stats we could see on DRK armor.
My guess is DRK will sacrifice health or defense to gain back MP, or to use powerful attacks. He can probably also use MP to cast defensive spells. So if you go all out on Attack spells you won't survive, ect you get the point.