I don’t understand what the whole fuss is about. Imagine this: 2000 pages worth of Qur’an and its exegesis that looks at interpretations of not only the orthodox Sunni exegetes but also of all other sects, including the Khawarij and the Mu’tazila. That in itself makes accessible discourse that was previously unreachable to all but specialists.
There is a review of this book here, which seems to highlight both the strengths and the problems with the commentary:
It seems to me that other than at two key points, the commentary is both faithful to tradition and far more thorough than anything else that’s been released so far. Reading a book doesn’t mean believing and accepting everything inside it.