To get anyone who is a current JW to be open to taking an honest look at the WTS and the Bible, they need to have already questioned something in the organization or the Bible themselves first. Otherwise they're just full on regurgitaters of the "truth," they've been indoctrinated in.
For myself, simple research into the 1914 belief started my decline. 607B.C. not being the year that any secular historian accepts as the correct year of Jerusalem's destruction, which really should be enough to go, "The WTS got this wrong. This should be backed up by secular history, that would be what makes this belief right and what makes it believable. Our beliefs are always touted as being backed up by worldly facts, why is this one wrong?"
The original date of 1914 was preached to be the end, not the beginning of Christ's rule, they changed this to fit under their, "new light," premise. Then you find out about other failed dates, 1874-1878, 1925, 1975, etc... And every time the WTS dismisses the claims with, "While some in the organization felt this way, this was never the direction of the GB." If you don't go, "Well then why were these dates in your literature that you disseminated to your followers?!," then you're still too indoctrinated with your beliefs about the "spirit-directed" organization to move forward. This started my decline. Then that lead to questioning the Bible itself, then the loss of faith altogether.
There has to be a self-made crack in the armor of their belief before any further progress can be made.