There are currently long debates going on with 3W about the subtle meaning of words and how they are supposed to prove the WTS has the correct doctrine. Even as a JW I always noticed that it was impossible to prove a doctrine to people in the field. The fact that 2 Christians can discuss topics endlessly without any conclusion shows me that God can not possibly be going to destroy every non JW simply because they could not be convinced of Watchtower doctrine.
The bible says very little about doctrine, besides Pauls discussions to show Jesus is our Ransomer and means for everlasting heavenly life. Jehovah's Witnesses preoccupation with Watchtower centric doctrine seems to distract them from the biblical message the a person is to keep their minds on Jesus as the means for salvation.
The concept that we are in the Last Days and in Jesus presence since 1914 is spiritually damaging. A Christian serves God out of love for God, a JW serves with the view that they will get a reward within the next few years. This only leads to dissappointment and hence the large number of burnt out JWs.