I don't want to sound condescendant, but are you not basically doing packages ? Instead of standard packages your distro gives you, you have "custom" packages t

I don't want to sound condescendant, but are you not basically doing packages ? Instead of standard packages your distro gives you, you have "custom" packages that also contain more specific installation instructions (write file with specific content, set environment variables, ...). I know that PKGBUILDs in Arch allow you to do such things if needed. Bonus: now even configuration files can be linked to the software that needs it; when you remove a software you also remove all the files related to it and there are no leftovers.