I would like it if they brought a lot of the wiki they have for the game over into the game. There are character descriptions and tid bits there that I feel could be in game. Like stuff for when you analyze the MGs in battle such as a character bio or short description based on what we know, or when you advance in the story or world the MC could just write things down and give details on progress in game or in their relationships with the other characters.
Unfortunately, sounds a bit like endgame update stuff after everything has been introduced and implemented.
A book of lore and information would be appreciated though. I like this game in so many ways it's been a great time.