While playing through MC hardcore again - in MCMMO no less - this past time, there were certain bottlenecks in my progression that showed that there is still a large amount of tedium left in the game.
What is tedium in Minecraft's case? Tedium occurs whenever, despite one's best efforts, they cannot progress in a timely fashion based on skill or a reasonable understanding of game mechanics alone. This manifests itself in a few ways and generally results in performing repetitive tasks with little to no reward - i.e. being bored for hours.
Observations and solutions:
1. Finding enough ender pearls to locate the first stronghold takes almost as much time by itself as everything leading up to that point. Suggestion: every enderman drops a pearl. Endermen spawn more frequently. Perhaps endermen could spawn more often in desert biomes (where there is little water, which they're allergic to). These changes would cut down drastically on the amount of time needed to find pearls, which you typically need 8 or more of at least to reach the end, when they become trivial to obtain. Why change it? There is nothing enlightening about searching for endermen for hours except in some kind of Zen sense. Changing this would increase the odds that a user would experience the end content that was labored over.
2. Randomness in enchantments is unnecessary and leads to "dice roll" mechanics, wasting time on farms just for a chance to get the enchantment you want. Suggestion: enchantments have a cost based on their rarity and can be applied at will to a book. For example, a mending or infinity enchantment alone might cost 30 levels of experience, but you would be able to choose it any time you wanted to. Why change it? This cuts down on repetition and slot-machine-like gameplay. It doesn't make any sense the way it is now and anyone that claims it's for balance or fun reasons is lying.
3. Villagers are basically useless unless you breed them like cattle. Suggestion: multiple. First, add roads connecting villages when they're within a km of each other so they're easier to find. Second, add Dwarf-Fortress-like functionality to villagers - if you are friendly with them, add the possibility to give them tasks that you pay them for, like zoning an area for excavation or farming. Third, add arbitration so you can trade between villages profitably. Why change this? As it is now, villagers are basically just another time sink that, at best, can be manipulated to clear up the slightest bit of tedium. Now instead of searching for endermen you can just farm 10,000 wheat, sell it to a farmer, give a cleric 40 rotten flesh and a bunch of emeralds and then all of a sudden you can just buy the pearls... Assuming you can find these guys in the first place. These changes make it more likely to experience villager content and uses dumb NPCs to do dumb NPCs tasks like mining and farming, which are virtually the same all the time and are only time sinks.
4. Certain materials are far too rare and the solutions are either sophisticated but ridiculous or nonexistent. MCMMO resolves a lot of this, but there should be dedicated solutions in the vanilla game. Suggestions:
Slime - farmable from clay at a certain rate
Bones - farmable from gravel at a certain rate
Gunpowder - farmable from gravel at a certain rate
String - can be crafted from leather
Saddles (finally) - can be crafted from leather
Ender pearls - see #1
Emeralds - see #3
Wither skulls - drop every time
These simply require too much tedium in one form or another to get a reliable amount. At least by making these changes the onus of collecting them would be put back into the hands of the PLAYER, not an AFK operator sitting at a farm (regardless of the wisdom of being able to create a farm). The goal should be to increase play, not AFKing.
5. Wolves and ocelots are too slow and weak. Suggestion: make them faster than players (as they would be in reality) and make them more aggressive. I can't even keep track of the amount of time that I've stood around waiting for these quadrupedal animals to catch up to me while I jog at a leisurely pace or the number of times I've lost them because they're in an unloaded chunk, just for them to spawn next to me 3 hours later in a mine. The player should not be punished thus for bothering to tame them.
6. Travel speed can be greatly increased with blue ice roads through the nether, but why only go this far? Suggestion: add a waypoint/Lloyd's beacon/town portal system. In the interest of balance, this could require an item that's a mixture of an eye of ender and chorus fruit to use and the beacon would need to be made out of end city material. After all, if you've gone through that headache, you're probably all done not having something like a town portal.
7. Shulker boxes are nice but are a half measure. Suggestion: make them accessible through the inventory just to cut out the half-step of putting them down and doing what you'd already otherwise be doing. This is just a straight up quality of life improvement. The current system is a hack.
8. The Wiki is almost certainly needed to complete the game. There are games out there like Alchemy which rely on combinations as a braindead task to kill time, but due to the added dimension of position, the combinatorics makes achieving all the items you need to complete the game impossible. Suggestion: integrate any necessary knowledge from the Wiki into the game through AT LEAST discovered books. The fact that you need an outside reference to complete the game in any mathematically likely fashion is frankly embarrassing for a game worth multiple billions of dollars. Is this a designed product or the worst programming language ever? Information on how to go about things could be found in books in dungeons, villager libraries, mine shafts etc. This would challenge children to read instead of watching a WHAT'S UP EVERYBODY on Youtube and would eliminate the need to tediously tab back and forth between MC and a browser.
9. Many Terraria gameplay features have been copied, but terrain generator remains an obstacle and rewards are poor. Suggestion: if you're meant to locate a dungeon, a mine shaft, a woodland mansion, a pillager tower, a stronghold, ruins, or monuments to experience all the game content, then make them denser or at least more likely. In my last server I did a /locate on the woodland mansion. It was LITERALLY 25 km away and took me the better part of a half hour to fly there with elytra and rockets. I would have never found it without operator commands. What's the point? Case-by-case suggestions:
Dungeons: more numerous, spawners can be picked up with silk touch again (if the player wants to AFK farm), chests contain books with references to what you have to do in the game. How about an item that increases your health?
Woodland mansions: either vastly improve their loot (some magic weapons would be nice) or make them more numerous
Monument: sponges should be able to be used in the hand, monuments should be more numerous and there should be an item that improves your breath capacity
Nether fortresses: should permeate the entire nether because it's not interesting looking for these things. They're the only landmark worth looking for in the nether anyway. I often get lucky but sometimes I don't.
End cities: it's absolutely boring waiting for chunks to load in the end. There should be a similar road system ("fairy dust trails?") between cities like my suggestion with the villages. Make it harder to traverse the void if necessary, just don't ask us to travel for 20 minutes or more just to find a city that's virtually identical to something we've already seen.
10. Repair has had quite a journey, but unfortunately it's still annoying. Suggestion: add the anvil from MCMMO. Non-enchanted tools can be repaired using only their raw material, not experience. Enchanted tool? Better imbue it with mending or else the default system is in place. The caveat of this is that mending would be much easier to obtain given my suggestion in #2. It basically means that repairing banal items is easier, and if you plan effectively then you can still maintain your high-end items indefinitely without the increasing cost of repair.
There have been other things I've thought of before, but this pretty much covers the main stuff. It's baffling to me that Mojang refuse to make a sequel to the game with actual game design improvements while they sit on their hands saying the graphical update is impossible and doing things like adding bees to the game, like honey is something we need (even though it is, of course, once more already an item in Terraria and Dwarf Fortress). If they wanted to add something from Terraria then add more travel options and if they wanted to add something from Dwarf Fortress then add programmable villagers. I will literally pay full retail price for a sequel with these features; I'm not asking them to do it for free at all (even though I've easily dropped over $100 on this game to begin with).
Feel free to tear this apart now or add your own suggestions. I will not respond to patronizing remarks about how the status quo is balanced or challenging or anything though - the game is pitifully easy when you know what you're doing, only tedious.