Off course it is, because you should be loop modeling instead! Loop modeling is much more effcient than box modeling and equally easy to do. They do share part of the tool set but the basis of loop modeling is not usually a box but a better organized start cage thats a drawn polygon then split up to form a more manageable cage.
Box modeling tends to converge into boxy shapes (known as box modeling syndrome), whereas loop modeling targets just that problem. Now it isnt that box modeling cant be done to reorganize into loops, its just that the starting point is counter productive to the end result. So people who start out with box modeling tend to converge to boxy models because they aren't paying attention to the loops they need instead they work on the loops they get!
Theres huge difference in end result between doing what you need and getting something out fo the system. Now if you want a example of loop modeling in action. See how your cage flows shoudl define the muscles.
A example of quite successfull loop modelling can be found here:
http://www.highend3d.com/maya/tutorials/mo...torial-303.html
Notice how he splits up the exact loops he needs the model to have up front. Its much easier than to redefine a box mode l later. The advantage is many fold you concentrate on whats most important all the way, but also you design how things will deform later. Anyway you should always build loops whether or not you box model but ist just easier to start with the main loops up front it keeps you more focused on the issue.
PS: i prefer a different approach to both of them, its more closely tuned to how humans draw, this for the base cage off course.