No doubt the temple mount was the holiest place on earth almost during the time of the 1^st and the 2^nd temple (or since Abraham). 
The house of god located in Jerusalem is also a biblical fact especially for the future. This is the town God has chosen. The term “Zion” is a little floating. Isn’t it rather a term to describe where God lives in Jerusalem?
What’s about the other line of prophecies?
Why does God say to Ezekiel: “this is the place…” when Ezekiel knows this place- the temple mount- very well?
According to Jeremiah 7:13 and Jeremiah 26:6+18 the temple mount has the same doom as Shiloh.
But what happened in Shiloh? Psalm 78:60ff gives us an answer. God moved from Shiloh to Jerusalem. He left Shiloh. He said that he will do this again to the present mount of the temple. Don’t you think God will move again? Isn’t it possible that he has already left the temple mount?
If this is true the new “Zion” has to be another peak of the mountain range in Jerusalem because the location of a temple in Jerusalem is fixed. But Jerusalem has grown over the years.