This was a great book and the possibilities for a truly great film were definitely there. But the casting decisions completely wrecked the movie. Hanks is a great actor to be sure, but lacks the smarmy, morally ambivalent characteristics needed for the lead role. Jeff Daniels would have been my choice.
Putting Melanie Griffiths in, for eye candy reasons, is understandable, but again, she did not portray the depth or ambivalence, so need to pull this off.
This movie is a great example of how every decision, even those early on in the movie production can make or break a file.