1 Timothy 2:5
The current JW understanding of that text is based on a "legal" or business meaning of the Greek word for "mediator." But it is not proved that Paul had only a "legal" meaning in mind when he wrote, especially when he tied the word "mediator" with the phrase "ransom for ALL," not just for 144.000.
But neither do Paul's words indicate that Jesus is now a "man" in heaven. He was a man when he gave his life as the mediator, that was Paul's reference in the verse. Jesus was able to be the mediator precisely because he was a man. But Paul is not implying that Jesus is still a man up in heaven. Greek scholars point out that the word for "man" in this verse is an anarthrous noun (noun without the definite article "the"), emphasizing again the relationship between his status as a human and his mediatorship: he was human at the time when he gave his life as a ransom.
Therefore, I do not accept the WT doctrine that Jesus is mediator only for 144,000, but neither do I accept the doctrine that Jeus is still a man up in heaven.