Not a revalation of course...but "The Last Battle" will be a big revelation to all the Fundementalist out there if they do it right.
Lewis was hard core Anglican and the fundementalist have accepted him as a great teacher and author without reading deep into his writings.
In "The Last Battle" the group that is allegoried to basically be the Jew/Christian side of Abraham's family tree is the group fighting with Aslan. The Calormenes are basically the allegory version of the Muslims...though they have traits of many groups that Jew/Christian would consider "Idol" worship.

One of the most telling passages in the book comes when a Calormene is judged before Aslan. The Calormene has worshipped "Tash" his entire life with great loyalty and cannot understand Aslan allowing him into 'heaven' as it is because he is still claiming loyalty to Tash. Aslan basically says that his worship to Tash was done in good faith and with a good heart and with purity and everything done in that manner is actually worship to Aslan...even if not intentional. Lewis is basically stating the basic and not so controversial Anglican belief that there are many ways to the Lord that only the Lord knows and that judgement is for the Lord and not for people.
This belief is VERY MUCH against the closed mind Christ that the fundementalist want to scare people into accepting and I can't wait to see thier reaction when the movie hopefully portrays this correctly.