Pickman's model
I am aware of the wonderful things that Islam has done in the past, and had Islam continued to develop in that way, it would be a lot different today. Islamic art and literature are of high standard, or were one may say. The religion seems to be going backwards, becoming more hard line in the face of the modern world. I strongly suspect that the diatribes against Western culture are driven by fear. When people see what the rest of the world has to offer, Islam and Sharia is a poor substitute.
As far as I am aware, no other mainstream religion advocates death for anyone leaving it, and this is not in the abstract, this is happening today. I have no doubt that the initial teachings of Mohammed have to an extent been altered by his brutal successors, frightened that their young people will leave, thereby lessening their grip on society.
Islam is as much about command and control as it is the worship of Allah. The excuse given by the Sunni and Shia, when breaking the prohibition of the Koran on killing other Muslims, is that the Sunni/Shia are not 'proper' Muslims, therefore killing them doesn't count.
Give Islam a few more decades/centuries and it will be where Christianity is today. I fully accept that the path of Christianity to where it is today has been bloody, but Christianity has 'grown up', something that Islam is still in the process of doing. Christianity went through its phase of command and control perversion, but it passed.