The best way to limit the growth of Jwism is to educate non-JWS. An educated public will take care of the rest.
As a non-jw - I absolutely agree with you. An educated non-JW can say much more than an ex-JW or JW who is in. I'm working on that....
I've now got non-JWs approaching me who ask me to talk to their JW friends, neighbors and relatives. I may be too kind to do heavy handed cult extrication but just praying that one day the seeds grow.