Hi there, SpiralLinux creator here. On one hand, I agree with you that it is indeed “just Debian”, which was a primary goal of the project. There is absolutely no dependence on me or the SpiralLinux project for maintenance of the installed system. However there are a huge number of changes from a vanilla Debian installation apart from the package selection and theme. A lot of the changes are quite low-level and would be difficult for many users to discover or implement on their own. These changes are achieved via proper configuration files that survive future Debian updates. You can see what has been modified and implemented by downloading the live-build recipe tarball from the SpiralLinux Github page, and look in the config/includes.chroot/ and config/hooks/normal/ directories. Where feasible I try to properly comment the reason for the changes.

I’m not trying to pull away satisfied Debian users, but I believe there is a significant number of users that would like to run a pure Debian system but aren’t doing so because they find the installation and initial configuration for some reasonable polish and niceties to be a bit too much work.