The issue with Jack Reacher is that he is completely devoid of material possessions. He wanders around, catching rides or buses sometimes and othertimes walking. He has nothing but a wallet and a toothbrush, though his financial state varies. He buys cheap clothes, often at a secondhand store when he needs new ones. He has nothing in the way of assets but his mental and physical abilities, and those are made out to be formidable. He's something of a math savant and is very observant and situationally aware, with both military & investigation experience. And most importantly, he is huge and very strong and experienced in hand to hand combat. The point with Reacher is he is supposed to be some sort of indomitable force of nature.

I don't think Cruise did a bad job with the role, and I think heights are exaggerated in readers' minds and don't necessarily translate on screen.