The idea that al-Ghazali is some sort of lone giant among Islamic jurisprudence and that he decided the course of Islamic history, should in truth be cursed and smashed into pieces. It is like the 1257 disaster at Baghdad, mistakes in historical readings and do the Islamic study an injustice. Al-Ghazali was not unique in his views and the ideal that reason is subverted to faith to a degree is a precedence within Islam, not even the Mu'tazila said that reason is something that transcends faith or so forth. Even so, assuming we take the Mu'tazila line, we are left with their precedence, that being the Inquisition of the Middle Abbasid period, that period and jurisprudence that partly caused the rapid decay of the Abbasid polity in terms of its power. Mu'Tazila were also extremely rigid in terms of jurisprudence, more so than even what you call Wahhabi, in short, the Mu'tazila believed too that there was no such thing as cultural considerations and that one may inflict a punishment upon someone before they knew what the crime was. The Mu'tazila reasoned this opinion of theirs, it was not something that was made a necessity of religion by Islam, so they reasoned toward an extremely regressive format of rule similar to say the Legalists of China. If this is who will lead the charge in Islamic history, then the Islamic world would certainly be far worse off than it is now (assuming things are too precarious at the moment).