The Dock generally displays all running apps, you can just click on one. I agree about the screenshot one - but this is often a power-user use case.

There are a bunch of ways to eject a drive: 1. little eject button in Finder, 2. Right click on drive on desktop -> Eject, 3. Drag drive from desktop to Recycle Bin (this one is weird, but intuitive for long-time Mac users I guess). I admit I may be misinterpreting what you mean by "secondary" optical drive.

System-wide zoom is mega-situational. I'm sure it's useful for those with visual impairment, but I've never seen anyone use it nor have I had use for it myself. This is like complaining that high-contrast mode in Windows does not have an easy-to-access menu.

On my mac my keyboard has an eject button right next to f12(volume up). If I press that then the primary disk drive ejects its disk.

If I had two disk drives, I'm not sure which it would eject. I suspect that this is what WayneDB was referring to.

To chime in on the screenshot issue - the only real way around a shortcut is to have some sort of Window... And you'd have to have some sort of setting that hides the window. I think Gnome has something like that.

Screenshot: you use grab.app, which is included in the utilities folder. OS X has shortcuts, yes, but at least they all give consistent, immediate feedback, something Windows, Android and the various Linux desktops still don't get right.

How about Command-Tab? Click on the icons in the dock.

Capture a screen? Grab.app

Eject secondary drive? Drag it to the trash can.

You got me on the zoom in/out. I don't know that one. But I could make an argument that this one is not a shortcut, but the only command, as it falls under accessibility.