Stefano,
Thanks for getting back to me so soon!
The Editor role should ideally be able to view all subscribers, as well as all newsletters.
I'm not sure why these (as well as all other pages) are not enabled for the admin pages, as your documentation states "Enabling access to the editors means blog users with editor role can use the Newsletter. Every part of the Newsletter plugin from the configuration panels to the newsletter composer panel." If this is not the case, then the documentation should be updated to reflect this.