((Finally found one of my fav tutorials again–click through for larger image and source and give it a read, particularly the “Form vs Function” section and below. I don’t care if you’re an artist or an RPer, this is important for everyone depicting superheroes and muscular characters in general in whatever medium: art, writing, what have you.
It is my personal opinion that Asgardians are far more on the heavy side, as they do not go to the gym and do thousands of reps to perfect pretty abs. They lift things, throw things, wrestle things, slaughter things, and generally exercise in combat or combat training, and, thus, would not have those perfectly defined bubble muscles or the triangle-top torso. They probably even have some pudge, seeing as they feast and drink after successful battles, and they are rarely unsuccessful. (I like Coipel’s drawings of them, ps, because he seems to follow this and makes them look like they have mass. A little less so for his ladies, but that is not what this post is about.)
Also, sidebar, Asgardian dudes probably have [lots of] chest hair. It is a fact of life that humans (and, most likely, humanoid alien/diety things) have body hair, and I highly doubt Thor, Balder, Hogun or anyone in Asgard is scheduling waxing appointments. Poses some interesting questions about the ladies, but, again, not the purpose of this post.
In any case, I don’t know about you, but I actually find the unsculpted, massive sort of pudge-coated strong-man body with a coat of chest hair pretty damn hot. I’d actually like to see my faceclaim put on a few more pounds (I find the bulkier Superman body with his hairy chest much more attractive than the shiny bronzed Immortals one), but c'est la vie de Hollywood. Probably won’t change any time soon, but one can dream.))