You're never going to reach people truly in with shock and awe. You WILL get plenty of people that are on the edge or simply accept everything to start thinking, perhaps even children. Why does Jehovah let these people in the Kingdom Hall - the KH is the JW safe space, their preaching guided and protected by angels - break that bubble and you have the beginnings of doubt. Plenty of people have been persuaded by people simply breaking the rules in halls or convention.
Illustrations?
- when I was young my abusive step-dad punched my biological father at the 3 day convention. That stopped my entire biological family except for us and my grandmother to continue going. They were always so so but they went through the motions. This was during the time the JWs got a number of bomb threats in their conventions and they always talked big game from the stage about how nobody ever got hurt and they even announced the threats but stopped evacuating the site. My cousin to this day, even after 25 years of not believing always remembered the questions he had - the angels have to protect us against bombs and they couldn't even protect a punch.
I have many anecdotes where people, entire congregations even will leave the organization for the slightest reasons. Many people are on the brink but are there just in case or because they believe in the protection that many die hards swear by. Break that sense of protection by emulating them or fooling the organization, some will harden but many will fall.