It will never happen but my dream is each D&D book in a slip case with the 300 page "reading copy" AND a slim "rules summary" book for easy reference in play akin to complex board game rules: complete but very concise.I get that I started with 1e MM and BECMI. I found the 1e MM very inspirational, BECMI less so. So I would say I like the 1e lore amount pretty well, though that could very quite a bit. I will say I was less engage with long lore entries like for orcs (though I liked them for demons, devils, and dragons - so probably my monster bias more than anything)
That being said, all the information that goes into a monster entry for LevelUp or Twilight Fables (shout out to @Sacrosanct 's awesome monster book) is incredibly interesting and inspirational. However, I have found that while I like to read those type of monster books, they are not as useful at the table for me. So each has a different function for me.
A lot of this is, of course, moot when we start talking about Beyond and VTTs. Many of my complaints melt away when I am running games on Fantasy grounds, for example: there is no page flipping to worry about for spells or feats or templates or whatever.