Big update! My model recently discovered the joys of Hip Hop Abs!! His midsection has been tightened up to look more like abs instead of bulges coming out of his stomach.
Other significant refinements made to the model include cleaning up the muscles on the back of his legs, and the back of his torso to show the trapezius, the lats, and the sacrospinalis (the latter of which becomes visible moreso towards the lower back).
I also completely revised the muscles of his forearms to improve the placement and relative scale of the long supinator and long radial extensor. I feel that their origin points inserting on the outside of the arm between the triceps and brachialis are now much better defined and more accurate.
All in all I would say the model is nearing completion! He still needs ears, but depending on where I'm going to take him, I may or may not model them. I probably will being that I've modeled ears in Maya and that was quite the task but not as hard as many have described the process. Thus it should be even easier in Zbrush right? We'll see!
The main thing I resolved about my model was a feeling that he was improportionate from the waist down. This feeling was cemented by tracing an outline of him onto paper and measuring his height in terms of heads. I know you may be thinking, "He's a superhero, of course he's improportionate! Look at the size of his muscles!" That said, he should still be the right height, and I discovered that he is about 1/2 to 3/4 of a head too short! The midline of his thigh and knees fall short of where they should be! So by the next update, he will look the way he should - 8 heads tall.