For those Who didn't see Minecon live there's alot of updates coming your way wow
The major one coming is ....
NETHER UPDATE
And also a mountain update due to the vote.
For mountains we get goats and new mountain generation aswrll as deep snow....Winter world never again...
The nether update contains new pigmen mobs which act like pillagers and villagers combined.
There's also nether forests made of netherwart and pigmen boars as mobs to drop food.
Soul sand also has a blue flame ontop when set on fire so cool.
Other news is Target blocks that send variable amounts of redstone signal depending on where hit on the target.
Honey blocks look good too.Cant jump on them and good as ladders.
Here's the link to the page for all stuffs
Don't know at this rate if resetting nether would be a good idea with all the new generation.

https://www.minecraft.net/en-us/article/everything-we-announced-minecon-live-2019

will the new nether chunks not simply be the updated nether?
I have a few portals in the nether linking a long nether-path to the overworld so I'm like 60% against resetting the nether but if you did it wouldn't be the end of the world. i think johnnyboy has a base in the nether though and i've seen some other extensive roads in there. other users will need to weigh in.

The current map has been left to continuously extent for infinite extents so this means you have plenty of space to build.This is also relevant to the end.Usually see the live map.Anything that's not black has been explord but the black is space to explore.This also means don't go around exploring everything like running to the border

Surely there's a need for a chunk-manager tool that would "age" chunks based on how long ago they were visited, whether a player actually entered the chunk or just came within range of it and whether anything was ever built nearby, so if a chunk was only ever glanced at once two years ago it can be deleted and later regenerated with the new content.

I feel that is a super obscure thing to have, but since minecraft has so many players it could be a possibility and quite a useful tool, although I imagine that it might make standout chunks of new generation, not sure if you remember previous times updates to chunk loading happened it would result in areas with flat walls of new generation where they were say 5 blocks higher or lower in new generation which might be unsightly and not so useful either way good to look into.

I still remember with acacia spawn when whole shop stalls disappeared via chunk errors
Chunk holes we had to fill over and for some reason were full of water.
Ive found bees on the server though have found if they sting you they die so be careful.