There is absolutely no doubt that Islam needs reform right now. The need is far more urgent than it has ever been. And the book does an interesting job of advocating exactly that, book, though a bit extreme at times, and over the line.
There is plenty in Islam which needs correction, and plenty of things in Quran which we can do away with. That much is true. And yes it is true too that violence, in some ways (specially in terms of call for Jihad), is condoned by the religion and the Quran. In fact, at times, it demand violence. But saying that every terrorist become so mostly because of the religious teachings, with little or no impact of the surrounding, the society, the economic and the educational background is grossly misleading. True, there are Muslims who have lived a privileged life in West and yet has gone to Syria and Iraq to join the extremists group, but that number is all by all means a small one. And Muslims living in West are certainly much less likely to join groups like Boko Haram and IS, as compared to those already living in the Middle-East.
Also, the author blames every wrong practice in any Islamic country directly on Islam itself (almost in all but one or two cases), with complete disregard of the fact that those practices reflect more of the regional cultural traditions and activities than Islam itself. Though Islam did prove to be a fertile ground for such ideas and actions, and in order to present a complete picture, I believe that is necessary to present too.
Also, the book feels like going in circles and honestly is a bit repetitive. The author conveyed her points in first 50 or so pages of the book. Rest 150 pages were just conveying the exact same idea after mentioning a different incidence which amplified how much is wrong with the Islam being practiced today.
Everything said and done, though I might disagree with some of the points the author mentioned in the book, and her blatant desire to avoid citing the statistics which won't support her point of view, on a broad level I absolutely agree with her. The Islamic world needs a "Renaissance" and can certainly do with more than one Voltaire.