That it is. The reasons why are not particularly clear, and the choice feels rather arbitrary, though.
Personally, I don't think that has any discernible benefit to a doctrine that is so emphatically monotheistic and that takes as a given that there is perfect and eternal value in the Qur'an.
Indeed.
The Qur'an is just scripture. As such, it could never, even hypothetically, have much of an impact in any religion.
The context, however, that is very much significant. A religion - or even a doctrine such as Islaam - is no more and no less than what its adherents make of it.
Shia Islaam, I have learned, hold the Al-Bayt and the Twelve Imams in a regard that seems to me to be fairly comparable to the idea of a Son of God. Of course, it is very easy indeed to simply point out that there is no clear support for such an idea in the Qur'an.
In that sense, Sunni and Ahmadiyya Islaam have somewhat better cases for arguing that they do not idolatrize their prophets and their scripture. But still not much of one, mainly because they still saddle themselves with a lot of focus on God-concepts and not nearly enough on actual religious practice.