There seems to be a bit of FUD in this "discussion."
Some things from my perspective:
1. Pd's library/path mechanism is largely oriented toward *local* libs first and *global* ones later, ie. download externals to individual project (sub)folders. I believe the centralized loading was added later on in Pd-extended. If we follow the "programming language model", this might be similar to installing a Python egg locally or globally. I don't see how supporting both modes of working is a problem.
2. IOhannes convinced me, over time, that the "stdpath" loading mechanism used by the "extra" folder is problematic as it adds too many (sub) search paths by default and it becomes harder to tell/control what's being loaded. The "better way" is for people to specify those externals paths directly, either with the user search paths and/or declare. There is much less ambiguity as to what's going on at the loss of "just put things in this place" ease.
3. As suggested by Alexandre, I wrote a PR to help address how declare search when using -path & -lib by having them search along user search paths as well:
https://github.com/pure-data/pure-data/pull/205. I feel this is a much closer method of using declare to how other programming languages handle such things, ie. Lua's require.
4. The Pd Documents path (aka ~/Documents/Pd) is simply a helper location for beginners. It is only a regular user search path added by default (when desired) and does not search subfolders. Nobody has to use it and it can be disabled at any time.
5. Yes, the macOS hiding the ~/Library folder is problematic for many users as they don't know how to show it and are afraid to modify things within it. I've recently taught classes to beginners that are just learn gin the concept of a "file system" as they grew up mainly using "mobile phones" ... Plus, ~/Library/Pd was also a "kitchen sink" std path with the issues listed in #2.
6. I've attempted to provide some solutions to various issues outlined over the last year regarding [declare] and folders. It would be helpful to get more feedback earlier on in testing / experimentation, rather well after a release. OTOH if I attempted to do work for free on Pd that pleased *everyone*, I suppose I wouldn't bother.
(7. Code talks.)