I would usually agree, but in this case, Jack Reacher's size and over-powering strength is an essential piece of the books.
The movie was good - but it was more an adaption of a story created by Lee Child, that just happened to have the same name as the books.
Which is one of the weakest aspects of the books IMO. In this day of guns and readily available weapons, having a guy that relies on hand to hand versus relaying on over-powering strength is more realistic IMO.
Maybe 30 years ago that aspect made for good story but not now.