Normal Player should also be able to set warps using the command /warp set [name]
There can also be a config to limit the number of warps a player can have.

this would be great to have!

In my mind this is better understood as a "public homes" system than "player warps" (mostly because warps are stored at the World level, whereas homes are stored at the Player level).

This leads me to a question:

Which of these do you think is more intuitive to use?

1. Homes with a public/private flag
2. A separate root command for public player homes. (e.g. /phome or /pwarp)

If 2, I'm open to suggestions for the root command name, as I'm not the biggest fan of the two above...

I might take a crack at this. At the moment I am leaning toward simply adding it as another nbt compound in the existing world_data.dat over a dedicated pwarp.dat file.

It would have this structure:

pwarps:
-<name>:
     -headYaw: <f>
     -pitch: <f>
     -x: <f>
     -y: <f>
     -z: <f>
     -WorldRegistryKey: <s>
     -owner: [<i>]
     -private: <b>
     -blacklist: [<s>]
     -whitelist: [<s>]

Great, that structure seems reasonable.

I'd recommend extending (or, at least using internally) MinecraftLocation for storing these, handles some of the nbt interactions for you