The controversy of the trinitarian vs. the unitarian doctrine dates back to the early history of the church. It's clear that many Christians never accepted the trinity as the "central doctrine of Christianity." When Arius argued against it in the fourth century, he had the support of many including some of the Bishops. It was only when the trinitarians consolidated their power through political means that it become "orthodoxy." And the unitarian belief continued down through the ages. So, it is not an exclusive Watchtower doctrine as many seem to indicate.
The topic has been discussed in length even on this site. It has not been resolved for two thousand years. So, it will remain a subject of discussion in the future. But for the average Christian not skilled in theological debate, the very human description of a "father" and a "son" is understood without the mystery of a complex explanation from a theologian.