> No, detecting when some text is selected and performing a copy instead of sending the signal
Ugh, that sounds awful! The Copy action should always be the same action, and it should always copy only, and never do unexpected, possibly harmful, things.
Re: Maximize. FWIW I have always preferred the OSX implementation -- it allows me two different window sizes that I can choose myself, and toggle between them. But I'll concede that if you come from Windows, having one of those choices taken away from you feels more natural. :)
Re: OneModifierKeyButNotCtrl+C. I can't speak for Windows, but this does not work on Linux. You can screw around with xmodmap and some apps to your heart's content, but you will never configure a GUI/DE-wide key combination for Copy that works in all apps. This is what you get, for free, on all versions of MacOS, ever.
Unless your argument devolves to "source code is available". In which case: OK I guess.
Re: macOS inflexibility. I mean, sure. And sometimes flexibility is critical. Other times, carefully-chosen defaults and strong consistency is more important. Anyway Linux's flexibility does not provide a path to solve this specific UX design error, so it doesn't help me here.
Don't get me wrong. Linux is great, and I choose it and use it happily for many things. I choose other OSes (all Unixes though!) for other purposes.
I have specific requirements for my desktop/console/terminal environment which might not match yours. MacOS meets them with default configuration plus some minor tweaks (e.g. focus follows mouse). Linux is not flexible enough to meet those needs, so I do not choose it for that purpose. All good.