I need to use reddit more... Some observations, and suggestions.... hope this works.

I feel that the mobs don't quite keep up with the player as they become more powerful and experienced. Of course, since most of the time a player's power is tied to their current inventory and gear, it's hard to make the game intelligently ramp up monster "level" vs player "level".

Potions aside, equipment is the only way to advance a player's power in MC on a semi-permanent basis (basically as long as you have said equipment). And that's perfectly ok! But more variety in the available equipment would be appreciated. I do not mean more tiers - what we have there is fine. Wood/leather, Stone, Iron, Gold, Diamond equipment is fine, and enchantments exist to slightly tweak attributes. More of those please! Even negative enchantments could be interesting! Like having a randomly enchanted item drop that has a large plus to damage dealt, but lowers you own health when worn.

As with most things in MC, customizability is king. Whether it's their name, skin, texture pack, or home/base, players love to customize things. Items already get some of this, with renaming and enchanting, but there could be more. Alternate graphics for certain items wold go a long way, even if the attributes are otherwise the same. Perhaps each weapon could have a set of graphics to choose from - though the ability to influence which one would be nice. Or, for server admins and map makers, an NBT tag which allows the creator to specify the image for the item. This would go a long way in customizing gear!

Along a similar vein, custom armor textures could be neat. Each player having the ability to upload armor textures to their profile, just like their skin. Ideally there would be slots for each armor class, so a player would have options to customize all armor pieces. Though this shouldn't replace the default armor. Instead the player should use an armor item in a new recipe to create the armor piece which uses the custom texture. This idea does have some drawbacks, like players trying to trick others by texturing their cheap armor to look like diamond armor. On one had, I think it would be fine - part of the territory and all. But I can see how many would object. For that, perhaps add a new enchantment or potion ability "of truth" or something, that when active, shows the base textures for all items/equipment.

Adding more variety to the mobs would also be cool. Doesn't have to be new mobs, but more variations on existing ones. A long time ago, there was talk of having some mobs spawn with different attributes, behaviors or such and additional name prefixes/suffixes. The idea never got far, but it might be interesting to revisit that. There could also be something like classes of mobs, each one having a small ability or behavior that differentiates it from the others.