Really? What pages are those discussions on? I confess, I only read back through about 10 pages before beginning to post; tearing through the reams of discussions is usually not the most productive use of time, as I've found while going through other 100+ page threads.
Hopefully Islam's rise is a big shock to the world and the treatment of the Prophet is tastefully done-- a big game-changing event two centuries into the game is a perfect fit (compare to the Mongol invasions) and depicting Mohammad respectfully is just a courteous thing to do. Heck, if need be, just mention Mohammad in the invasion-warning events (compare to the rumors of the Mongols events) and then present the rise of Islam as starting a little later with the Rashidun caliphs.
Firstly: You better read through the entire thread, just to be safe.
Secondly: If you mean that Islam would be an ass-crushing Empire in every game, then that has already been discussed and rejected. In most games, Islam will proabably not create a huge empire. Think of it, it would take a human touch to create an empire that large with so few starting resoruces, and the most butterfly conditions you can find. Find the discussion regarding Islam for more info.