From another forum.
Dear All, Salaam
1. Allah decides to sent His Final Revelation
2. He chooses Muhammad (S) to reveal it.
3. The Revelation is completed as testified by itself.
In my opinion, I find it hard to believe that:
Allah and His Messenger made no efforts to leave it in a comprehensive form. We all know it was being written down by "Noble Scribes" on parchment (The Book tells us).
Instead of leaving it as a Book, Last Revelation was left (according to stories) as Dr. Shabbir says:
".. For example, it was revealed in seven 'qirats', variant readings (even different words), it was written on bones, date leaves and stones, some verses were lost, Sahaba Kiraam used to dispute with each other on how each of them had heard the verses from the exalted Messenger (S), that Hazrat Uthman had collected the scattered Qur'an and burnt the variant copies, and so on...."
Even a human author makes more efforts in leaving years and years of his writings in a better shape if he plans to publish it.
In the light of the above, I can safely conclude that the arrangement of the Qur'an was done by The Messenger himself per Divine Guidance because one does not take a Book that is to be the source of inspiration and guidance to mankind for all times and leave it in a form that causes confusion and suspicion.