Liches Get Stitches

[Grumpy RPG Reviews]

More than 10 years ago I wrote a book on liches for 3.5, "Lords of Sorrow." For the past few months I've been working on updating it.
Right now it has;

• 6 templates (for 5E) or 6 prestige classes (for Pathfinder)
• Rules for creating special phylatceries
• A discussion of the transformation (they can feel themselves rot into a skeleton)
• 25 or so new feats
• 12 or so new spells
• 9 new monsters (7 new monsters, 2 new templates)

I'm posting this here because I've entirely made up my mind about it being for 5E or Pathfinder - feed back is welcome.
Also, what would you want in a book on liches?