@BaronBattleBread It only resets the blocks within 10 blocks horizontally of the bedrock in the centre of the pillars. So you could potentially build a tower around the pillars with a 5ish block gap between the pillar and the tower if you wanted to.

@Dennari43
It won't make a difference for most mobs. The only ones the y coord will effect are the ones that need a specific y coord like ocelots, bats, squid and slime.

Nice Christmas hat btw.

Here is the relevant buggy bug report:
https://bugs.mojang.com/browse/MC-95437
Upvote it if you want it fixed...or don't if you don't...

If I understand it correctly, and I'm not sure I do, whether or not that spawner converts successfully depends on if the world saves between changing the spawner and and it spawning its first round of mobs. If it does save the spawner converts successfully, otherwise not.

I'm not sure if this is correct, but if it is you should be able to force this to happen by logging out immediately after converting the spawner and waiting >45 seconds before logging in again. Maybe try it with a couple of spawn eggs you don't want and see if it works.

Pretty sure changing a spawner doesn't depend on anything. The environment only dictates whether or not the spawner will spawn, you can change spawners to whatever you want regardless of the blocks or biome around them.
They also shouldn't ever revert unless there's some form of chunk corruption.

I realise people have posted before saying spawners have reverted/failed to convert. I'm confident this is actually because of lag rather than anything else.

Ah the old triple chest bug ! If you keep adding them in a line every chest has the inventory of the two net to it.
Also try doing making them around corners. This makes things even more glitchy and you can end up with phantom chest blocks you can walk through, or even 'linked' pairs of double chests that open simultaneously :)

Something you might find useful is that you can convert between sand and red sand.
Last I asked this was fine on the server according to staff. Presumably because it still requires you to gather all the resources, doesn't duplicate anything, and you sill have to go find a mesa to be able to do it. Anyway, hopefully this helps :)

Bonus mobs: Baby variants of zombies, pigmen, husks and zombie villagers.
Added degree of difficulty: Collect all of the above with Jack o'lanterns on their heads.

Regarding this bit:

@WBlaine But, this is still oversimplified. A majority of the mining being done on the server
occurs at Y =< 16, where all diamond ore is generated.
...
But now to determine to actual value, you have to consider another variable: how often people mine in this fashion.

You really cant get a decent conversion without taking into account how people mine for different resources. As you showed mining at y<16 you end up with about 3 iron per diamond, but if I'm mining for iron I generally go caving at y>16, making for a much higher ratio more like the 11:1.

It's even more important for gold. If you assume people only mine at y<16 then 1 stack of gold is worth just over 140 diamonds. However if you assume everyone mines for gold in a mesa at y>32 then 1 stack of gold is only worth 12 diamonds.

You've obviously also got to think about how people value these things. Redstone is a great is example. Based on abundance a stack of redstone blocks should be worth about 15 diamonds, but in my experience people will sell for a fraction of that because the fools don't value redstone.

TL;DR This:

@MisterChris717 I'd say that we can't really pin down a specific price for iron per diamond.

Worked this out a while ago when someone else asked a similar question, comes to about 11 iron per 1 diamond if you account for fortune 3.

Just wondering, would giving them mining fatigue help at all. Not sure how KillAura works but shouldn't it make them able to hit you considerably less often?