If AQ won control of SA, then they would make the next fatal step outside of their borders, and 20 minutes later, mecca and medina would be glowing craters. Then we would discover if Mad Mo's Insane Murder Cult could exist after Allahs all-powerful black moon-god rock was shown conclusively to be no match for a nuclear warhead.
That's the "alternateve B" end game to this dance, the only question is whether it happens in one year or twenty. Personally, I'd take my chances on a Saudi civil war, resulting in the deaths of 100s of 1000s of pro-jihadists. Similar in scale to what happened to the communists in Indonesia a generation ago.
A bloody take-no-prisoners civil war in Saudi Arabia might be exactly what Islam needs.
I just suggest that you be careful for what you wish for. Consider the results if the Islamists win and take control of Saudi Arabia?
In doing so they sea their doom. Needless to say the United States will not allow AQ to control 25% of the world's oil reserves so upon the defeat and exile of the House of Saud the US will invade and defeat the terrorists. This will not only have the effect of eliminating the terrorists paymaster but also put American boots into the "holy cities" of Mecca and Medina. These wackos actually believe that Allah protects these cities and will kill any invader That approaches them. The presence of American soldiers getting their pictures taken in front of the black rock will forever wipe this theory of invincibility from them and reduce them to a minor threat of a very small number of extremists. The benefits will be that we will finally have a representative democracy int the new nation of Arabia.