For a TF2 model like this proportions are required, but not 'so' much anatomy. As long as you follow good base orthos on the type of build you want for the character you should be fine, but once you get into sculpting and texturing full blown anatomy is a must, and it takes months of a daily hours of sculpting to get…
Im more curious as to how you ended up with a result like this... Even though you dont have blender, try this for a start: http://cg.tutsplus.com/tutorials/blender/character-modeling-in-blender-basix/
After a quick review of your threads, you're better off going back to the modeling basics and just practicing with objects around your house and following tutorials. You're going to frustrate yourself jumping into character art. Start small and work your way up.