First of all I want to clarify I do not dislike their current design choice, I think overall it is a pretty unique design and was not what I was expecting from a dragon themed race/class. While I assume there more slender physique was the overall design intent to help further portray the Dracthyrs lack of melee prowess, ultimately I think the appearance falls a little short of what players expect from a draconic influenced race.
Taking into consideration that these dragon juiced experiments were created by deathwing while he was still the aspect of earth, I assume he would at least attempt to create them in his image, or at least in the image of the leaders of the dragonflights. When looking at other dragonkin races, you do indeed have the big burley brutes like Razorgore & Broodlord Lashlayer but even the spellcasters in the burning steppes look physically capable, even maloriak looks menacing (and assume he is the original Dracthyr) if not a little malnourished, but I assumed this was intentional to further show Netharions abuse to him.
So to conclude, I would love to see different body types introduced to the Dracthyr, while I personally don’t think I need mine to be roided up, I also don’t want it to look frail. More player choice is always a good thing when it comes to character customisation.