"For He [God] has not put the world to come, of which we speak, in subjection to angels."
If God has not subjected the world to angels, then just *who* has He given it to, to steward and govern it (under Him)? You guessed it: mankind. But not just any and all members of the human race--but those who constitute the body of Christ, the church. The original creation was placed under man; but we botched it up, in Adam. The new creation is placed under the God-MAN, Jesus--and all who are His share in His dominion.
Angels are important; and they have a job to do. But the Second Person of the Holy Trinity did not become an angel--instead, He became a man.
[Puritan quote of the day: "You that are weak, and are full of doubts, should go and lean upon those who are strong and who have full assurance." --William Bridge, in "A Lifting Up for the Downcast"]