I was a preterist after leaving the Watchtower Society, so I thought that the prophecies given in Luke 21 and Matthew 24 only could make sense for the facts of the destruction in 70 A.D. However, the prophecy clearly said that
"then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.".
but, this did not happen after Jerusalem's destruction. No one saw Jesus coming in the clouds of heaven with power. On the contrary, Jesus was and is absent in many of crimes committed by his representatives on earth. Jesus can't be the head of any church.