If they just got rid of all the dialogs (hide if seen already), then it would reduce the number of clicks by half.
Another thing that helps is to move the NPC dialog window on top of the others you need to click, to minimize the amount of mouse movement. It will usually pop up right under your cursor, making it faster to clear than if it was off in some corner of your screen.

Also, someone posted a mockup of a more efficient retainer UI: https://forum.square-enix.com/ffxiv/...up-pictures%29
You just select the retainer you want to deal with in the upper left, and the contents of the window change to match that one. No need to keep walking through multiple menu levels.