Before I start this thread, I have to say that I haven't given it too much thought as yet, so I'm not here to sell this idea to you, just to express it. If it is riddled with flaws, then so be it.
Here are a few posers for you:
Mecca is built on Seven Hills ( well, surrounded by seven hills, so nearly so...)
Although Dubai is part of the U.A.E. who is to say that it may not become part of a greater Saudi empire in the near future?
Mecca is under the control of the Saudi Royal family, a fact that may Muslims (especially Shias) are unhappy with. The Beast may wage war upon those who control Mecca in an attempt to gain control of it himself.
Dubai, is a city of greed, luxury and enormous wealth, which despite it's conservative Muslim facade, covers a number of vices.
Merchants from far at sea will see Babylon burn and smoke rising (oil wells set on fire).