I just wondered what people's opinion is on whether Galaxy should have an "Installer Maintenance Mode" where it simply downloads the setup files and keeps them up to date rather than installing the games directly. I ask this because it's a pain to have to manually download the local installers, which is my preferred method of storing my purchased games, and it can't even be done in a single click.

I agree, I'm asking this since day1.
But Gog probably won't do it :\
In the meantime, check Gogrepo.

Thanks, that looks like a useful tool.