And our capital shall not be Cairo, but Jerusalem

[Elok]

Because in an era of instant communication the location of your capital really matters for administrative purposes.

I'm not so sure. Don't you want a good local labor pool of qualified professionals to draw from? I'm sure Jerusalem has the necessary bureaucrats at present, but I think the whole plan is to Drive Them Into The Sea. They sure as hell wouldn't hire any of them, so the hypothetically-victorious Egyptians would have to transplant a big chunk of population to run their newly-enlarged country from their new capital. But that's something like the 85th-biggest problem with this whole cockamamie idea.