Being a sometime resident of Jerusalem, I tend to disagree with the theory that the Ophel mound was the location for the Temple, simply because the area is too small.
The spring itself is also lower than where the Temple floor would be, making transport of water rather difficult, depending on the technology used.
I believe there are/were recent excavations in the area to see if a structure existed; I do not know the results.
I recall the old quip: 'Ask two Jews, get three opinions.' When it comes to Christians, and especially iterpretations of 'prophetic' books like Revelation and Daniel, the fruit doesn't fall far from that tree! (In Romans 11:17-18, Paul writes to the Gentile Believers concerning Jewish Believers:
'But if some of the branches were broken off, and you, although a wild olive shoot, were grafted in among the others and now share in the nourishing root of the olive tree, do not be arrogant toward the branches. If you are, remember it is not you who support the root, but the root that supports you.'