Very well then...Ross may not have based his Superman specifically on Christopher Reeve (I believe he actually used a friend as the prime model) but he has given interviews where he stated that there is a significant amount of Reeve's influence in his art work and that he prefers this version of Superman. Many fans have also made the connection as well. Gary Frank (Geoff Johns's artist on Action Comics) also based his Superman directly off of Christohper Reeve.
I understand the need for a more muscled/action oriented Superman but the fact is that unless you cast a bodybuilder or something that is never going to be the case. Just because he's drawn at times as insanely muscled (Ed McGusiness's cartoony muscle bound freak comes to mind, and I love this version) this is not something that is possible for a film.