Even when I was still mentally in, whenever they would spew this whole "obey us whether it made sense or not" I would automatically think of Jonestown. Honestly, though, I don't think it would be that crazy. This is a company after all; they're more interested in making money than killing followers if things go south for them.
I also think straight up tithing is a little too obvious. @SummerAngel said they might start charging for certain things, which I think might be a little more realistic. Maybe start charging for a JW Broadcast subscription or the new releases at the convention. You know that little box that pops up on the app for the Convention Releases? The one that says "Have you attended the 2017 convention yet?" They could put a charge on those maybe.
Due to New Light on overlapping generations, maybe they'll come up with another 1975-like situation. That overlapping generation has to die out sometime, so whether they realize it or not, they are most definitely setting a date for Armageddon. Maybe they might publish when that year is? Like the overlapping generation has to die out by 2080 or something.