Evoker could have easily gotten 4 specs with 4 different roles
Range and healer are already established
Tank spec that would focus more on Black dragon like abilities
A melee spec that could focus on Bronze/Black Dragon like abilities
They have the mobility, they have the scales, claws tails, wings ,fangs etc etc, the fantasy of a dragon shredding their victims in melee while using breath and stuff is easily doable. But in Blizzards logic a bear with fur is more durable then a dragon with scales...