I think the majority of people who start searching for the truth about "the truth" are already on their way out even if they don't know it.
I've never imagined that regular "faithful" witnesses stumble across some ex-JW site that convinces them to leave for the same reason that no amount of information given to someone will make them leave. What typically happens is that something happens that touches them personally and makes them question things and it needs that trigger to get people open to the concept that it may be false.
They may be tentative, they may be uncomfortable, they may even feel the need to defend the WTS out of habit, but they are looking for confirmation that what they feel and what they think may be true.
That's why I think the personal stories and accounts of experiences that they can relate to and realize "oh, it's not just me / my congregation" are the most powerful convincers.
People by and large don't become JWs because of doctrine and that's why they don't leave when the doctrines change or get bothered that they make no sense.
It's all about personal need and personal issues and at some point the WTS will cause some injustice against them or someone they care about.
It's why the pro-JW types can spend endless time debating and defending the WTS and be unaffected by the information they are given. People chose what they want to believe. At some point they chose to stop believing and at that point start looking for counter viewpoints.