My wife came from a JW family, her mother was disassociated due to a divorce (from an abusive husband). Her grandfather was the first JW in the family and this was due, as he put it, to the JW concept of the hereafter. To him it was believable and he liked it. This also seems to be the main reason why many convert. They appeal to the idea of being "elect" and/ or inheriting paradise due to their faith.
The traditionally moral lifestyle makes them feel superior and able to feel as though they are on the winning side.
As for dogmatics, JW's alter theirs through issuing new Watchtowers.
Interesting. You say that many convert due to the JW concept of the hereafter. I will attempt to synopsize based on what I have read. There is no body/soul dualism in their view. Therefore, at the time of death, and prior to the resurrection, one simply ceases to exist. Post-resurrection, there are three alternatives: if one is faithful to JW doctrine, one will either be resurrected as one of the 'elect', literal
144,000 humans, to reign in heaven eternally with Jesus or be restored in paradise eternally, which they place here on (a perfected) earth, cleansed of evil-doers. Outside of these alternatives, one will experience a 'cutting-off', which from what I can gather, means that one simply ceases to exist. It sounds as though all non-JWs suffer this latter fate?
I fail to see what is so persuasive or desirable about this teaching. For one thing, it seems to be in flagrant contradiction of the Lord's teaching in the NT re: the eternity of suffering in hell, so I don't know how they exegete these passages to support their view.
I do see that, as you say, the sense of moral/ eschatological superiority could be appealing to our fallen, prideful psychology. It strikes me as an almost Manichaean view of humanity as divided between the good and the wicked according to rather superficial standards, which fails to take into account the reality of sin in the life of every man.
In learning about their 'theology', I am reminded throughout of the psychoanalyst Igor Caruso's characterization of the distinctive feature of neurosis as 'absolutization of the relative.'