Fuji has been milking a same cow, it begins to get stale regardless how good it is.
It's due time for new sensor.
Can Fuji sell enough cameras to pay-off the investment?
Not sure if I am an investor, especially with what Sony is doing with their A7 series.
Fuji nowadays resembles Canon of yesterday, they were also milking the same 18MP sensor in countless models and fell quite behind the other players on the market.
I guess the old 16MP APS-C Sony sensors are cheap nowadays, because the technology is polished and demand is low (who else apart from Fuji buying them?) So Fuji will keep using them as long as people are buying their cameras.
But I believe the competition from Sony FF and APS-C cameras is heating and can force Fuji to move to the newer sensors or lose customers. Had Fuji used bayer CFA as everybody else, the transition would have been painless, but they created an obstacle for themselves with that weird x-trans CFA, and, as practice showed, for no good reason.