I couldn't find anything with the keyword "pickpocket" in this section so I'm making this post now just in case word of this hasn't traveled to the bugfix -division yet.
You can pickpocket anything for essentially free, it doesn't trigger the NPC's "I've been stolen!" action or count towards the pickpocket -bar on the bottom.
Plus, even if you take something and close the window, you can pickpocket them again and again since the "Already pickpocketed" -flag doesn't get triggered either.

What you do is drag n drop -swap the item you want with any item in your inventory. Could be junk, could be anything. Could even be stacks of 1 gold coin.
You just swap em for each other and it doesn't even count as a theft, however the items you swap will have the "Stolen" tag on them, still.
Also to be mentioned, even if you wouldn't normally have the required pickpocket level (the bar goes red when you hover over an item) you can still swap it just as easily with this method.

I really hope this'll be fixed for release since right now you could essentially empty an NPC's whole inventory with a few coins or literal trash.

This still works on release.
Is there no intention of fixing this, would it break some other stuff perhaps on gamemaster side or?

For me this doesn't work anymore. You can not drag'n'drop items from the pickpocket window to your inventory. And if you drag'n'drop an item from your inventory to the pickpocket window it is not swapped - instead it just gets added to your targets inventory.

This, and if you're using a piece of coin, it gets added to their total. This does not work anymore.