Every time they* remake an old classic based on a book, they claim that this new version isn't a remake but rather an attempt to adhere more to the book's text. We heard this bullshit most recently with the Total Recall remake, but it happens all the time. And now it's happening with Ben-Hur.
The classic 1959 Ben-Hur is, itself, a remake. There was a silent version in 1925, and even a one-reeler in 1907. That version was based on a Broadway adaptation. This is material that has been done again and again, so getting up in arms about it seems silly. Hell, there was a TV mini-series in 2010.
Ben-Hur: A Tale Of The Christ is the story of Judah Ben-Hur, a Jewish merchant in the 1st Century AD who is wrongfully betrayed to the Romans by his best friend. He gets sentenced to a life of rowing galleys, but makes his way back to Judea and tries to get revenge. When he comes across Christ on the cross he sees the error of his ways and becomes a Christian. The book, by Lew Wallace (a Civil War general!), is considered the great Christian novel of its time - sort of the Left Behind of the 19th century.
Here's something interesting: Ben-Hur the book is now public domain (this is why they're saying it's more faithful to the book), but the 1907 version was a big moment in intellectual property law when it comes to the movies. That version never bothered getting permission to adapt the book, and Wallace's estate brought suit. The fight ended up in the Supreme Court, who ruled against the motion picture company, and so the precedent was set that any movie adaptation of a book had to be licensed and legal. The more you know!
The most famous scene in the William Wyler Ben-Hur is the chariot race. That sequence took three months to film. I'm sure the new version will take three months... of CGI rendering.
* you know, them.