Which issue, IDK. And to tell you the truth, JWs are becoming so far in my rearview mirror, I don't really think of them much. I mostly come here to listen to good community topics and to listen anxiously for signs of their demise.
So while I can't pick out any one issue like shunning, child abuse, blood, etc. I feel it's different for everybody.
Like for me, not being abused, nor having anybody I know who was abused, it's not an issue I can directly connect to personally. I think it's horrible. Whereas for other people, that is exactly the thing for them. Their hot topic.
The internet is the common thread. When I left, I had to order a book through the mail to hear the other side. Now with the internet, it's like you have multiple sets of encyclopedias that refute the JWs right in your home. If I'm a householder, I can find out all about them minutes after they left.
They've also got a waking-up to deal with. Where people are abandoning their beliefs in mystical powers and taking a rational approach. Where we're no longer having the debate about which religion to believe in, but whether to believe in religion at all.