Even if Egypt falls other than mass emigration of Christians the prophets of doom are lost as usual. Egypt is an economic mess that has squandered aid with little to show for it.
The huge army is supported by foreign aid. Job creation is nill and poverty is rife.
The best clue as to what an Egyptian Brotherhood rule would be like is a poorer version of Gaza. The miltary would likely be to divided to do much. We could see the tyranny and corruption of religious police.
Any notion that Egyptians will embrace the Magna Carta and Jefferson is misguided. Societies with submission as a key cultural component do not readily lend themselves to this type of solution.