The issue claimed by the parent is not just restricting user freedom, but not doing the right thing. Your points:
Pocket integration: not the right thing, at least not the way they rolled it out in Germany, but not a restriction on user freedom.
Removal of about:config entries: This changes in response to changes to the engine, and restrictions can make sense if they avoid mainstream users from being confused about their setup so they find it difficult to find help. The developers edition usually has a bit more flexibility here, for advanced users.
Move to WebExtensions: This massively increases evolvability of Firefox, which I expect will result in better security, better performance, and less interference between extensions.
Changing appearance: I guess things like this are a side-effect of moving to WebExtensions. Maybe they will be supported again as the API evolves.
Dropping bookmark descriptions: these are identified as a possible attack vector in https://bugzilla.mozilla.org/show_bug.cgi?id=1276819
Transmitting user data: this really does help developers and I find the way Mozilla go about this not to be sneaky the way their rivals are.