At the moment you click on an image and if the colours leak into it a bit it will just end up selecting 90% of the image making it a useless tool for some projects.
What I suggest is that Magic Wand could be updated to have a few more options to make the "Magic" more precise to what exactly you want to select.
1. Magic Wand should hover over 1 pixel at a time to get an exact pixel selection before the Magic happens.
1. Magic Wand by Color (Selects all exact copies of the exact color you select from the selected layer(s) or from the 2 colours you can switch between.)
2. Magic Wand from a list (Checkable) H: L: S: a: b: B: R: G: B: C: M: Y: K: (Can select from other layers if multiple Layers are selected)
3. Magic Wand to select x amount of pixels in x shape around the clicked pixel.
Implementing this would speed up so many projects that don't have the best resolution to delete or mass select specific colours to change them to another all at once from very few clicks.