SUMMARY Allow dragging a file or folder into the places sidebar. When doing this, allow Dolphin to open that folder for users to have a larger target area to drop the file or folder into. It seems more intuitive in graphical environments than copy, browse folder & paste.
I don't see how that would help. Yes, the main view would provide a larger drop area for the dragged item, but to see it, the user would have to have first dragged it over the small target in the places panel. Doing what you propose would be harder, because instead of just releasing the cursor to drop the user would have to move it over to the main view without accidentally moving over another places item and changing the view. Generic complaints about the precision required here should go in Bug 432735.