I think mine craft should include some form of tiered progression. That means, the farther you go, the harder it is. Here is why this works out good: Currently, zombies are super hard, especially in smp (lag) at early parts of the game, where you have stone tools. Now me personally, I move straight to the iron stage, but noobs especially stick on stone. Creepers can 1 shot you, until you get armor. Here's how tiering should work:
Tiering is determined by the things you craft (Armor and swords). Not by what you mine. So once you craft a diamond sword, you have advanced into the diamond stage (As far as swords go) Tiering allows the game to be only as difficult as you want it to be, so you can have it on hard mode, but it is only hard the entire time, not impossible at the beginning and easy towards the endgame (but not too easy). Once you have advanced into a tier though, you can't go back.
Unarmed stage:
You have no sword or armor at this time. Mobs do little damage (1-2 hearts per hit) and creepers do 5 hearts. You can kill a mob in 6 unarmed hits at this stage.
Mobs do not drop anything at this stage
Wood stage:
You have a wood sword, but no armor. Not a huge improvement. Mobs do 1-3 hearts damage, and require 4 hits from a wood sword.
Mobs drop half the normal amount
Stone stage:
You have leather armor, and stone sword. If you craft a sword, the mobs can be killed in 3 hits. Armor causes mob attack to be buffed to 2-3 hearts per hit, and creepers take 7.
Mobs drop the current amount of spoils
Iron stage:
You have Iron tools and armor. If you craft a sword, mobs can be killed in 2-3 hits. With armor, mob attack is buffed to 3-4 hearts per hit, creepers can 1 shot you without armor.
Mobs drop 1.5 times the normal amount
Diamond stage:
You have diamond tools and armor. If you craft a sword mobs can be killed in 1-2 hits, but occasionally you'll come across a buffed mob(?) It is the same as a normal mob as far as environmental damage, like falling in lava, but it takes little damage from you sword or arrows. These mobs require 4-7 hits with a diamond sword, and have a different skin(?) Armor causes mob attacks to occasionally crit, like when you attack. Normal attack does not change though.
Bows:
Before a bow is crafted, skeletons are more inaccurate, and can't see you very far. This makes it so killing a skele with melee isn't so hard in the beginning. Once a bow is crafted, skeles have longer range, and hit almost every time.
Tiered progression would be an option when creating a world, or maybe just be in hardcore mode.
This reminds me more of an RPG, where enemies become stronger when you become stronger (like in Oblivion). Also the additional difficulty through lag on a server isn't meant to be. There is no way you can demand a rebalance due to server lag, as this just isn't meant to happen (and maybe with the code cleaning and stuff, this problem will become less noticeable).
When you start a game, on any difficulty, you can easily avoid aggressive mobs for as long as you like. Also you know how hard enemies are when you start playing on hard and thus you have to prepare yourself.
Minecraft is a survival adventure game, monsters are not supposed to get stronger the better your equipment gets (survival means you have a tough beginning and it gets better the better your equipment is).
Don't try to make a survival adventure to an RPG.
It's sort of an optional thing. Minecraft is divided into two main groups: Technical people - these are architects, redstone people, mob trap makers, and Adventurers - Explorers, fighters, spelunkers. This is to make adventuring a bit harder. I mostly stick with technical stuff, but I love cave exploring as well. It's too easy though, as in my weapons are too strong. I don't want to downgrade, but I want it to be harder. And remember, this would be a selectable option in world creation.
Tiering is determined by the things you craft (Armor and swords). Not by what you mine. So once you craft a diamond sword, you have advanced into the diamond stage (As far as swords go) Tiering allows the game to be only as difficult as you want it to be, so you can have it on hard mode, but it is only hard the entire time, not impossible at the beginning and easy towards the endgame (but not too easy). Once you have advanced into a tier though, you can't go back.
Unarmed stage:
You have no sword or armor at this time. Mobs do little damage (1-2 hearts per hit) and creepers do 5 hearts. You can kill a mob in 6 unarmed hits at this stage.
Mobs do not drop anything at this stage
Wood stage:
You have a wood sword, but no armor. Not a huge improvement. Mobs do 1-3 hearts damage, and require 4 hits from a wood sword.
Mobs drop half the normal amount
Stone stage:
You have leather armor, and stone sword. If you craft a sword, the mobs can be killed in 3 hits. Armor causes mob attack to be buffed to 2-3 hearts per hit, and creepers take 7.
Mobs drop the current amount of spoils
Iron stage:
You have Iron tools and armor. If you craft a sword, mobs can be killed in 2-3 hits. With armor, mob attack is buffed to 3-4 hearts per hit, creepers can 1 shot you without armor.
Mobs drop 1.5 times the normal amount
Diamond stage:
You have diamond tools and armor. If you craft a sword mobs can be killed in 1-2 hits, but occasionally you'll come across a buffed mob(?) It is the same as a normal mob as far as environmental damage, like falling in lava, but it takes little damage from you sword or arrows. These mobs require 4-7 hits with a diamond sword, and have a different skin(?) Armor causes mob attacks to occasionally crit, like when you attack. Normal attack does not change though.
Bows:
Before a bow is crafted, skeletons are more inaccurate, and can't see you very far. This makes it so killing a skele with melee isn't so hard in the beginning. Once a bow is crafted, skeles have longer range, and hit almost every time.
Tiered progression would be an option when creating a world, or maybe just be in hardcore mode.
It's sort of an optional thing. Minecraft is divided into two main groups: Technical people - these are architects, redstone people, mob trap makers, and Adventurers - Explorers, fighters, spelunkers. This is to make adventuring a bit harder. I mostly stick with technical stuff, but I love cave exploring as well. It's too easy though, as in my weapons are too strong. I don't want to downgrade, but I want it to be harder. And remember, this would be a selectable option in world creation.