This suggestion is about having a look over all of the generated structures already added, and seeing if there's room for improvement. I do plan to do images! I just couldn't hold back from posting this straight away. Images might take a while still. Improvisations and changes to this post are without a doubt going to happen, so come and check it every now and then!
Should this idea become at all popular, I'd consider making a mod around it. I love the feedback you guys have, and it really helps me out. Please leave a comment and your opinion. Lastly, these are all ideas, and some of them are a little worse than others. That's why I'm posting here so that we can talk about it all. Thanks all! :3
Have the odd, empty minecart lying on the rails.
Generate little doorways in the mineshaft every now and then, dividing it up.
Generate a few small clusters of TNT laying around?
Overhaul the big dirt-floored room. Give it purpose. Add preparation or work area? Also, incorporate support beams.
Rusted rails instead of normal ones. Small chance of dropping a normal rail when broken.
Occasional skeleton skull lying around?
Skin change to the cave spider possibly? For disambiguation compared to the regular spider. Either a pattern on the thorax or differently coloured eyes.
Rotting crate block that generates every now and then? Will drop a random loot item/bunch of items when broken.
Burnt out torches that have a small chance of dropping charcoal when broken.
Perhaps lastly add a special plant. Like a glowing mushroom or something. Only spawns around the mineshafts, and very rarely. Could be used as a potion ingredient.
Maybe a new section of the mineshaft, that goes down roughly ten blocks and provides a broken ladder to travel between.
Rusted minecarts textures could be used in this area. Will drop normal minecarts when broken.
Slight texture change to silverfish blocks, as a subtle indicator. Not noticeable unless looked for.
Small changes to the pillar room. Perhaps add a stone pillar block type? 4 around the main one and have a chest on 0-2 of the smaller pillars?
Libraries should have variants of the bookshelves. Some half empty and cobwebby, with a small chance of getting a book or some string. Also add a completely empty variant, and a variant with a potion or two sitting on the shelf. These will randomly be placed as the bookshelves.
Half of generated torches should be burnt out versions.
Chest room could be decorated more. Maybe smaller if there aren't many decorations, but at the very least a few cobwebs and such could fill out the extra space.
Perhaps around the portal room could randomly have a few "corrupted stone brick" blocks replacing the regular ones? Corrupted stone brick being normal stone brick with a bit of an end stone look to it, literally as if it's been corrupted.
A New mob called "Holdkeeper", that looks like a statue. Will become active once a player has stepped within an 8 block radius of it. It is fire immune and generates in a new room called a "Hall". Roughly player size. I won't really elaborate much on this. It's not the best idea.
"Hall" room. Will consist of a few empty podiums and a few podiums with "HoldKeepers" on them. Podiums being something along the lines of a simple stone slab.
Have a rotting chest variant of a normal chest, that will break into nothing when mined. Alternately, could instead drop itself and be a collectable chest type.
Burnt torches around the outside.
Perhaps add an orange block to pull eye towards it, and relate it towards the desert temple.
Mineral block at bottom of well? Random chance of it being a different material. Most common being coal and least common being diamond.
Add a different type of sandstone to the game, to contrast the desert structures from the sand.
Generates in the mesa as well, using the specialized red variant of materials.
Make from a mossy looking smooth stone. When broken will give mossy cobblestone, which when smelted will revert to mossy stone.
Generate a lot more coal ore not only as a part of the fossil but around it as well.
Have a very minuscule chance of the coal ore generating instead as a diamond ore, no matter what level the structure generates.
Add a second type of a farm for melons and pumpkins, and let those types of farm generate.
Have a few farm shape variants. Squares and circles seem diverse, as opposed to simple rectangles.
Put a fence around most of farm, only devoid on the side of the farm facing the path.
Have a light source nearby farms. Especially in ice villages. Also maybe allow the farming villager to break the ice back to water?
Perhaps certain crops can only generate in certain biomes? Potatoes in cold, and melons in hot?
Make the dirt-floored house look all ruined, fractured and destroyed. Slight chance for an abundance of flowers to be growing inside, simply for fun. Remove the table thingy from it.
Redo houses to have paintings or other small decorations inside such as flower pots.
Have gold ore always generate at the bottom of the well.
Lava instead of water in the well for the rare zombie village, as well as a different block palette for the entire village. More stone-like and ruined.
New sandstone blocks to make the sandstone villages look nicer. A certain log is needed, so add a new tree called the "Rufbark" or something. Very few leaves, but if grown in any other biome, will generate much more leaves when grown, making it much more renewable as a resource.
New crop for the desert village as well, to match the biome specific crops. Perhaps cacti, with the addition of cactus fruit on the top. Looks like a succulent flower? Would need to implement AI so that villagers avoid cacti.
Priest tower thing should have a wooden floor, maybe even a carpet, and randomly colored stained glass for windows.
Install anvil in blacksmith.
Add a table block so that there doesn't have to be those pressure plate/fence things that click whenever they're pushed against.
Home gardens in a few of the buildings with fences out the back. Either that or animals generate in there.
Alter paths so that they appear different in different biomes. Also, snow should not be able to fall onto them, should they be covered in an ice biome.
Add a special exclusive building type for each biome?
New light block for the lights on the street, instead of the black wool and torches. Maybe a block that seems like a frame or wood, paned with glass, and a fire going inside of it? Unsure of what to use. Have villagers fuel it in their AI, but otherwise it'd be refuelable like a furnace minecart.
Alike the desert well it will also generate in the mesa, with a different variant of sandstone. Also, should use another color other than orange. I'd say yellow or light blue or light green even.
Mesa variant might have a different trap style. No pressure plate, but one of the four chests is full of death-related items such as skulls and bones and is a trapped chest instead. Will explode the TNT if opened.
The orange wool should be replaced with stained clay or even stained glass. It makes much more sense than wool and looks nicer too.
Use a different sandstone variant like the desert well, to create contrast.
Will use stone chest variants.
Maybe a few vines on the inside?
Lapis block on inside to replace blue centre block.
Other small alterations.
Perhaps make the floor differ from the walls, and the walls differ from the roof.
Add access to it via a ladder? Witches can't fly.
Maybe a chance of having a chest inside? Using the rotting chest variant.
Maybe have some form of window in it, so the player can look in and out to an extent. Also gives a little more to the dull design.
Spawn wet sponges all around it/inside it.
Add a lighter nether brick block to use as a floor. It feels very dark in the fortresses.
Use a new nether chest variant for the nether. Wooden chests seem out of place.
Maybe make the blaze spawners hang from a nether brick fence? Could really add a unique touch.
Add a second, chiseled form of obsidian. Maybe even a third if the situation calls for it. Use those variant to make the pillars seem more defined.
First, use an indestructible block that isn't bedrock. Maybe add a new block for that purpose. Make it pretty, of course. Also use that same block for the End gateway portal.
Should use a different beam texture and particle than the normal beacon.
Use the same additional block that the end fountain would use.
Once it appears, it would be very cool to show the effect of the sky brightening to an inspiring space-like sky, complete with whirling galaxies and the like. Maybe have like 3 different planets revolving about. Not sure how this could be pulled off, though.
Thanks for reading, guys. There's more to add, like a small amount of additional structures and changes to some of the smaller ones, as well as pictures and better descriptions, but I hope you all liked. Looking forward to feedback! ^u^