For lack of a better mod name, the 0-creaturepacks and its NPC version are replaced with a single "core" pack named 0-XNPCCore. It will have 1 dependency mod, the 0-SCore code pack by Sphereii. Inside the NPCCore will be a male and a female survivor (friendly), a bandit, an animal, and a zombie. These are all really template characters, fully functional, but there to enable the cores xml templates and demonstrate specific functions that characters can do in game (follow, heal, loot etc. ).
The idea is that modders can make expansion packs that have these cores as dependencies. So a modder can make a 1-Spiders pack, which will only include spider characters. Others might be soldier packs, villager packs, zombie medical staff packs, puppy packs etc. If you don't like spiders, don't load that expansion pack, or if its in an overhaul, remove that pack.
Each expansion pack will be self-contained to help avoid breaking other mods. All that is required is the characters files (.unity3d file), and the entityclasses.xml and entitygroups.xml files to add them to the game. Those entries would only be a few lines each if the modder extends from the templates provided in the NPCCore.
So in A20 we took an even greater modular approach, that I hope takes off.