Concerning the use of the keyboard shortcut control-option-shift-command-d set in the system preferences to invoke the "Run Dropzone Action" service: it may be of interest that the strange slowed-down emergence of the Dropzone panel only happens if the service is invoked when the keyboard shortcut is used. If you just use the menu selection Finder > Services > Run Dropzone Action, the Dropzone panel pops out at normal speed.
It's the use of the shift key in the key combination: this taps into a little-known variant of Quick Look. Normally, Quick Look on a file is invoked by selecting an item in the Finder and pressing the space bar; but if you select a Finder item and press shift-space, the Quick Look is invoked, but at a slow speed. It's the kind of thing that you would have thought would be configurable somewhere in Accessibility, but I can't see that it is.
So I'll have to choose a shortcut that doesn't use the shift key, unless I get to like the slow animation!