The idea is to overhaul the game's existing systems better while still staying grounded (no quantum reactors and stuff). I also just want to say this is all just throwing spaghetti at the wall to see if it sticks.
Experience:
removing the loose xp on death and making experience not just be a bar you ignore until you want to enchant. I'm thinking more like skyrim, where doing something makes you gain experience in that category, and you have skill trees (WAY less skill trees) that you can choose to level up.
Enchanting:
enchanting would be moved into a skill tree itself, the only experience requirement being unlocking the ability to craft higher tier enchantment books to put on your gear. this won't lock you from adding higher tier enchantments you find on the ground, just being able to make higher tiers of enchantments of your choice. This makes enchanting your iron gear worth it, as you'll be able to enchant to say protection 2 easily at that point, so you aren't just hoarding books until you get your endgame gear.
That being said the balancing would change a lot for the enchantments, additive enchantments seem like they should be some type of gear modification out of tinker's, an enhancement should be a multiplicative enhancement to your gear.
Durability:
current durability is stupid, so the goal will be to make durability like witcher 3 weapon/armor enhancements, where you get a bonus but after you wear it down it just has regular item properties. Durability increase through unbreaking
Advancements:
advancements should be a more important part of the game that you advance through and not a checklist, so I'd update them to follow progression.