It's not uncommon to see very advanced screen-capture programs that have many options, but we rarely use them.
You don't need to eliminate all the extras in order to create an intuitive program that meets your specific needs.
Greenshot is a good example. It combines screen capture modes in one program, making it simple and efficient.
It is possible to capture your entire screen or a portion of it. You can activate each of these modes by using a combination keystrokes or the icon in your menu bar.
You can save the captured image as a file or copy it to the clipboard. Or you can open it in an editor to customize your experience. The capture is automatically sent to the editor.
Greenshot is a great program for screen-capturing.