The GB can make a lot of tweaks and even more major over haul, and this would increase their members substantially. They have a business foundation that no other business has. They pay no taxes on profit, contributions, and land, or very little. They have a work force that they pay no salary nor benefits. They can terminate these workers at will with no consequences. Their same workforce is also their customers. Think about it, their customers make the products, and then buy the products they make. Their customers are completely loyal.
All they have to do is continue to tweak the blood doctrine until it is irrelevant, address past child abuse cases, and tweak disfellowshipping shunning. Once that is done their public image will increase.
The next stage, once they wired all the KH and the GB takes complete control of public talks, is to focus on the youth. Their only way to survive is having an engage youth that will create the next generations customers. I don't know if they have the vision or willingness to do anything meaningful in that category. If it is the same go to bethel or be a pioneer then I don't see much growth. The Caleb and Sophia videos are a start in the indoctrination process, but it won't last once the kiddies hit puberty. Be interesting to see if they will ever start a private school for witness children, or perhaps an online school. I think that would be the best avenue for them to control their next generation of customers. Having the children never attend public school and the only information they receive is from jw.org