I think biotech will remove blood as an issue for the JW's within 20 years.
That just leaves child abuse, charitable status and shunning.
If a major Western country eg Australia, US, Spain, UK, Germany, France links charitable status with public benefit then the JWs will have a problem. (How can you claim to be a charity whilst you engage in shunning former victims of child abuse, for example?)
Other than that , its rearranging the deck chairs on the Titanic as Oubliette pointed out here