To unashamedly hawk my own thread again, this is the solution that will appease the most people:
Dragon tanks? Check.
Bulky playable dragons? Check.
Dragons with sexual dimorphism? Check.
The only people that this won’t appeal to are those that are hyper-focused in on having Evokers and/or Dracthyr tank for some undiscernible reason, even if the draconic tank fantasy can still be fulfilled in another way.
Moreover, this would also ensure that Dracthyr nor Evokers are contorted into something that they were never intended to be. Whether or not you enjoy their implementation, they do have a clear identity and vision. Inflating them to Drakonid proportions or making them facetank like an overeager Mage would compromise that.