They'll never drop 1914, theres no need for them to drop it. But eventually they might just change the meaning of what happened in 1914. For example, they could reinterpret it to say the tree stump was only unbanded in 1914 and since then has been slowly regrowing and doesnt represent the ruling kingdom until fully regrown at the great tribulation. And just slide forward Jesus rule, the kingdom coming into power, etc, to occur at the great tribulation, while leaving 1914 as the time of unbanding only and beginning of the separation of the wheat from the weeds.
95% of JWs would swallow that hook line and sinker.