In Photoshop I click the color picker and automatically have the eyedropper tool at my disposal. I don't see any reason why XD should not react the same.

This is just one example of SO MUCH stuff that forces me to click more than I normally would in other software, like PS or ID! You are building software to make future software to be planned more easily. You may want to start with your own. It's so obvious how the designers of XD seem to have no clue how their big siblings work...

Sorry, this headline is misleading. It should say something like 'Automatically switch to dropper when hovering over an artboard with color picker open.'

Currently, sampling a color takes 3-4 clicks—one of them more burdensome simple tasks in the Xd workflow. It would be more efficient if, after clicking the Fill or Border color box, the pointer automatically switched to the dropper if you hover over an object on an artboard. Click the color box, mouse over to the object you want to sample, click the object, and the sample color fills the original object.

This would only work when the color picker is open, and you'd have to close it to return to normal tool function.

Agree. Especially now, when eyedropper icon disappeared from the main Fill or Appearance panel, and is hidden under color picker box.
It is very often used tool, probably not only by me, and now we are 2 clicks further from grabbing colour from the screen.

Before last upgrade it was like that:
1. click the eyedropper icon
2. click desired colour from screen

After upgrade it is like that:
1. Click the colour of Fill or Border
2. Click the icon of Eyedropper
3. Select colour from screen
4. Click somewhere outside to close the Color picker box

Agreed. It would eliminate the need for a separate eyedropper tool, which is confusing anyway. I often click the color palette looking for the eyedropper functionality.