As far as I am aware they will never reset the end/nether, however that would be good for shulker hunting. However, there is going to be a new survival server up and running soon (I think it will be ready when the server is updated to 1.12 - PC edition), so if you want a fresh break in the other dimensions maybe go into an entire new world or just go somewhere else.
The question is a good one, as I wanted to know this when I first started. But for the people that have spent hours (and I mean HOURS) of work making farms in the nether/end (chorus farms, for example), it wouldn't be fair to reset the other dimensions.
Limo