Zarvan, they thing you are forgetting here is that most of those who 'committed blasphemy' haven't actually done that. Many of them are unaware of what they did, like schoolchildren mixing up verses, or they are framed into this. Blasphemy isn't committed in most of the cases and it is innocent who are killed for no reason. You seem to know about Islam, now tell me, does Islam allow any primary suspect to be killed or first reviewed with atleast four witnesses if he actually did commit the crime? Going my logic, anyone who is pointed at for committing blasphemy should be instantly killed; it doesn't matter if he actually was involved or not!
I don't recall, but a killed from Qureish was let gone for a murder in Muslim court, because he had three witnessed, not four. Why don't you imply this law here and see how the cases drop dramatically? Remember, the punishment for false witnesses is harsher than your blasphemy punishment.