Corel has a very simple linear gradient editor where you can define "stops" and colours for them and there is a bar that shows the result live. Other gradients in Corel DRAW are made interactively by dragging the mouse over the drawing sheet and/or choosing the parameters from comboboxes or spinboxes.
Phtotshop, Illustrator and InDesign, all have a similar way of defining gradients. So does PaintShopPro and many other design programs.

Probably the users prefer this way...