I would like to introduce this suggestion, as one that can enhance replayablility, end game content and that connect to the lore.
I started to think about it when I came across bookshelf in D3 and would only get some gold from it… For those who played Diablo 1, bookshelf was always nice to find and a great source of power.
lets get to the point, there is a lot to do with a simple bookshelf. See it as a source of intel, knowledge about the world of sanctuary and beyond, there’s plenty way we can use this. In a game that has such lore and dept there is no limit on what intel you can find, even more in an open world.
Makes us incarnate the sucsesors of the horadrim. Angel, demon and ancien tomes could give intel or knowledge that accumulate in the “book of Cain”.
That knowlege could then be researched (or spent) to open up thematic side quests. Its way more imersives and fun than warping to adventure mode locations, do listed objectif, get reward and redo.
Intel within bookshelf would be revealing dungeons location, secret passages location, hidden treasure. Intelect could be literaly an additional source of power creep attraction. At that point it would be valuable to gain some intel find beside magic find. That would make player caring not only about the drops they get, but the content they acces. Because it would allow characters to find exclusives location, and where it leads you is a trill that adds replayablility.
Bookshelf can be found anywhere from open world to high lvl dungons.
They could have hidden affix and then if you have enought cumulated knowlege, certain affix become visible to you.
Aside intel or knowlege, here is some idea of what could contain a bookshelf:
Lore, book of skills, magic scrolls. It would be nice to get some exclusive usable magic scrolls that dont belong to characters. Maybe of angel, demon or ancien origins.
Crafting plans, cube receip, some low tier could be learned forever wile others would be usable, offering differents goals and replayability.
Special rune word receip, yes we do want the old special runeword back and together with new rune trigger system. Some new type of rune could help doing so without messing with socket numbers. Enchant type of rune could be use into the cube to add the trigger&effect to a specific gear, using only the base item to create uniques runic item. Enhance type of rune could be use into the cube to upgrade the proc or the effect part.
-Charms, we do want them, not necesserly in their former aspect. You can rework them charimg a gear slot independent from the gear itself so you can switch either without affecting the other.
that would limit the quantity without affecting inventory.
Treasure maps that gives the location of an unclaimed hidden treasure. They could contain loads of gold and jewels or chest with same drop rate as worldboss for solo player. Special relics like the cube and the scroll of faith. Fixed lesser uniques like in D3 adventure mode maybe. Special maps, inspired by the pactole. These treasure map could lead to a free cosmetic.
Prophetic quest, it is written when and where you will encounter these challenging quests. You’d get special mods affecting your character for the duration of the quest. Some quest you get debuffs or tricky mods for a challenging different playstyle oriented quest. Others would grant you buffs giving power to chalenge hier lvl or harder content. It would be nice that a profetic quest may grant the ability to solo multiplayer stuff like a worldboss version for the quest.
Actualities, would spoil about when and where the next few event will start. Or literaly grant acces to some multiplayer coop or pvp event. Potential treasure goblin raids location. Anything about actuality, like the weather lol.
Other than papers we should not find gears or gold directly in bookshelf. I mean, its everywhere else. Maybe some jewelery box with random ring, amulet, gems along with gold would be good, but stay realistic.
-Dungeon keys, and that unnamed item that imbue gear with the affix of a unique would fit well.
About the progression, I am sure that replayability is way more apealing than endless leveling. To achieve that there must be enought choices so it is possible to restart over and over the same character, and have a differant game play. To push it furter, it would be best that even if im using the same skills, other choices that I have allow me to still have a different build and playstyle.
Thats it for now, some of the idea listed was as exemple but I stand for the main idea of knowledge and I hope players would enjoy such content.