The WT likes to quote ad infinitum that the central doctrine of the Christian faith is the Trinity. They quote some Catholic sources, yadda, yadda, yadda. It is a great misdirection. "Look here and not there" sort of thing.
The deity of Christ is really a by-product of historical facts - the death, burial, and resurrection of Jesus the Christ. Obviously, if Jesus raised himself from the dead, while he was dead like he predicted that he would do - then that is something ONLY God could do.
But, the real central doctrine of the Christian faith that the Watchtower goes to great lenghts to obscure, confuse, and misdirect is the doctrine of Substitution.
John MacArthur explains in less than 1 1/2 minutes: