At this point I wouldn't be surprised if in future expansions, enmity was just baked into the tank mastery trait and they changed tank stances to be DPS stances because newer players can't seem to grasp the idea of pressing one button to gain aggro.
I think the game moved past the point of 2.0-4.2 tank design. At this point I would just like to see auto cleaves from bosses again to teach dps to respect the front of the boss and to teach tanks how to face the boss away from the party.
Multiple things are to blame with how easy and simple tanking has become at the cost of accessibility but I think better tool tips would help as the first step. An instance at like lvl 30 that "tests" you current job role would go a long way in acclimating newer players. Nothing crazy just a simple game of hold aggro and keep mobs away from a target.