There is of course a great deal of talk about reforming Islam these days, and just about anyone from Tariq Ramadan to the Saudi King, to people who actually see what is wrong with Islam and want to reform it, can legitimately claim the title of the reformer of Islam. But that is because the question of what exactly "Reforming Islam" means remains open.
The most successful reformers of Islam within the Muslim world are not Wafa Sultan, Ali Sina or Irshad Manji... but Muhammad ibn Abd-al-Wahhab who created Wahhabism, Hassan al Banna who founded the Muslim Brotherhood and Osama bin Laden. And while that may seem insane or absurd from a Western perspective, after all three men inspired orgies of mass murder and horrifying brutality-- they did indubitably try to bring Islam closer to its roots. The problem is that Islam's roots are more rotten and darker than its branches.
From the Islamic perspective, reforming Islam requires a purer Islam. From the Western perspective, reforming Islam actually requires a less pure Islam that is capable of implementing such foreign to it ideas as tolerance and co-existence. By contrast Muslims believe that whatever problems there are in Islam are the result of human corruption and innovations added to Islam over the centuries. A pure Islam is their final solution for ending the constant corruption in Muslim countries and creating a Caliphate run under Islamic law.
The question then comes down to just what is it about Islam that needs reforming. From the Western point of view, Islam's expansiveness, aggression, violence and intolerance are what need reforming. From the Islamist point of view, they are the hallmarks of what a pure Islam should be, intolerant of any intellectual miscegenation and unwilling to accept anything less than absolute dominance in the name of Allah.
There is talk that Islam needs its own Martin Luther, but that is exactly what Islam does not need. Islam already had its own Martin Luther in the 18th century and the Salafist bloodshed that was unleashed then still echoes in the suicide bombings today. Nor does that kind of religious reform usher in peace, so much as more war. And Islam certainly does not need to move any closer to its roots when Mohammed's bandits pillaged, looted and raped their way across what is modern day Saudi Arabia in pursuit of anyone who did not believe in Islam, or in the exact same form of Islam as they did.
No reform of Islam that leaves in place the absolutism of Islamic law will be at all helpful to the Muslim and non-Muslim world. And it is precisely Islam's claim on temporal power by way of Sharia that is at the root of the Islamic problem. Because there is no such thing as a private Islam, only a collective Islam. The Islam of the Ummah. A Muslim alone either assimilates for a time or goes insane, both of which can be seen from the interrogator's logs of captured Al Queda terrorists. Islam is not a private faith, but a public one. Its piety is in its outward displays of obeisance to Islamic law hide private corruption that is against the law.
Because of its claim to temporal power, Islam is in constant conflict with both the Muslim and the non-Muslim world. Its scholars ever present themselves as candidates for revolution, their fatwas key for legitimizing murder or tyranny. Wars, rebellions and brutal crackdowns are all routinely provided with the imprimatur of Islam, with a Fatwa or two to legitimize the notion that a ruler or a rebel or a terrorist is acting in order to impose Islamic law on whoever he happens to be killing at the moment.
While devout Muslims insist that corruption in the Muslim world is produced by a lack of Islam-- in fact it is produced by a surplus of Islam. Islamic law, reformed or otherwise, is not the solution to their problems, and polishing the codex down to the naked edge of a blade that Mohammed would supposedly approve of, and then slitting the throats of everyone who disagrees will solve nothing. Religious law is not the solution to human corruption, political transparency and democracy will always work much better than a dozen Imams poring over the Hadiths at checking corruption.
To truly reform Islam... Muslim clerics must do the impossible. They must give up power in the name of true purity. As long as Islam is tied to temporal power, it will remain innately corrupt, as will any institution that attempts to exercise power. When Mosque becomes detached from State, then Islam will cease to become a political tool and can actually be purified.
But it is precisely because Islam is a useful political tool for claiming temporal power, back to its roots in the desert when Mohammed built an empire by claiming to have received prophecies from an angel, that it can never be reformed and remains intermingled with violence. Only if Muslims were forced to choose between participation in the civilized world and Sharia, could Islam ever truly be reformed.