Redesigned Enchantment System (Slots and more)

Instead of having some enchantments be incompatible with others, equipment can have a certain number of enchantment slots. Some (or most) enchantments can take up multiple slots.

This should be done because, for example, choosing 3 of 5 enchantments is much much more interesting than choosing 1 of 2.

In addition, curses can give slots to an item instead of filling them. Most enchantments can have curse counterparts. (Instead of unbreaking, fragility, instead of sharpness, dullness, etc). This allows for much more customization.

Grindstones can remove the most recently added enchantment or curse, and actually give it back at the cost of levels.

Combining enchantments can add them (so a level 2 book combined with a level 3 book gives a level 5 book). This is to make low level enchantments valuable.

The prior work penalty should be removed. It currently heavily discourages using low level books and punishes adding enchantments to an item over time (instead of combining all the books first and adding them all at once). Anvil costs can be higher to balance this.

Similar enchantments (knockback and punch, flame and fire aspect) can be merged. This is so that players get the interesting decision of which piece of gear to put them on.

Finally, XP rewards can be rebalanced so that all of the activities in the game (exploration, combat, and mining) all give a comparable amount of XP. This is so that players, instead of going to the nether and mining quartz, do whatever they find most fun.