It isn't a part that requires stellar acting skills, so the casting is more about the right physical type and age (Adam Baldwin was a great candidate for older Jack Reacher, but not the young-to-middle years anymore). The absolute requirement is that he not be a prissy, midgetory, sportscar-driving wannabe. I.e., *koff*... the current casting.
I see that recasting Jack Reacher is also a thing over at IMDB.com, so we're not alone. :O
And my newest nominee for the "What the hell was that?" Sports Hall of Fame comes from last night's Cal Football game against Washington State: Buzzuh? Damn, why is there no slo-mo replay of that sucker?