The Watchtower implies that since Jesus was "sent" by the Father that therefore he must be inferior to the Father:
"Is not the sender superior to the one sent?" Should You believe in the Trinity
While it is true that a sender can at times occupy a superior position that the one who is sent, the fact remains that a sender and the one sent can be equal in terms of nature. A man may send another man, however they are both equally human. Likewise the fact that Jesus was sent by the Father does not mean that he has a lower nature than the Father.
The Watchtower says: "Thus Jesus illustrated his own position as one being sent by God to do God's will, just as a father sends a submissive son." Should You believe in the Trinity
The watchtowers example is heplful: A human father can send a submissive son, yet this does not mean that his son is inferior by nature (ie. less human) than his father. In fact human sons are always considered equal by nature to their fathers !
A son who comes to you sent by his father should be given equal honor as his father, and should not be demoted by claiming that he is some sort of lesser being by nature than his father.
"That all men should honour the Son, even as they honour the Father. He that honoureth not the Son honoureth not the Father which hath sent him." John 5:23