Yes, just keep doing that. I run several Linux boxes with systemd, all of them without hostnamed.
Forcing all your users to use the One True Way on a complicated system usually just means you're ignoring many legitimate use cases. Microsoft still does that on Windows (APIs and ugly registry entries over everything) - and while I cringe everytime I see it, I still recognize that the approach has value for some situations.
Many of the daemons for systemd on the other hand are optional, which I personally find to be great. I can use the ones I need and leave the ones I don't.
As for the GUI: Why use a text file? That might be a good use case for you and me, but a terrible one for someone not used to administrate *NIX systems. Why not allow both? As long as the file-based approach is not neglected, I'm perfectly fine with that.