Reddit reviews A World Without Islam

There is actually a book on it, haven't read it, ex-CIA guy apparently too. However, from a theological perspective, Muslims considered each truly revealed religion to be Islam(submission to the will of God), since the time of Adam, Noah, Moses, Jesus, and Muhammad, peace be upon them all. In any case, link to the book, haven't read it, can't vouch for it personally but if I recall right, someone I know recommended a look:

https://www.amazon.com/World-Without-Islam-Graham-Fuller/dp/0316041203/ref=sr_1_1?ie=UTF8&qid=1527258736&sr=8-1&keywords=a+world+without+islam

A former CIA analyst wrote a book with this very premise, called "A World without Islam". Its well worth the read, but the short version of his assessment is that most of the underlying conflicts in that region would still be there in some form or fashion, as you would just be replacing the current dynamic with a more drawn out version of the Eastern vs Western Christianity conflict.

For example, the crusades are often pointed to as an example of Christianity attacking the Muslim world and a root for many of our modern issues, but the crusaders were also perfectly happy to attack and loot Eastern Orthodox Christians they encountered.

Another example is the Israeli Palestinian conflict. By and large, Palestinian Christians are also opposed to Israel, and many of the founders of the PLO were Christians.

Can I suggest you read A World Without Islam by Graham Fuller, former vice-chair of the National Intelligence Council and Station Chief in Kabul for the CIA.