Probably few Witnesses would leave over this issue. They believe in a progressive understanding. What drives many is untoward events, bad behavior by others, personal offense, uncertainties, and a dictatorial, authoritarian structure foreign to many Western cultures. Perhaps the best approach, if you want to evangelize Witnesses, is to work on that level.
For my mother, who was never a Witness, the question was, "Is this right? Should Christians behave this way?" Bad behavior by authority figures defines organizations.
Another issue, as my young eyes see it, is that some simply do not wish to live within the shifting rules set by Witness authority figures.