However you are right that Arch tries to stay as close as possible to the source. This is fondamentally different than the debian (and thus all debian-derived distros) way of packaging where they aim for a fully integrated OS at the expense of applying their own patches to many packages.
The patches can sometimes bring issues since they can bring unexpected behaviour if you come from Arch and sometimes will help the end user tremendously since they won’t have to configure every piece of software to work on their computer.
This is really two way of looking at the issue: Arch is make your own OS and Debian has a more hands off approach.
demonsword