I would like a function so you can "drop all" of an item from inventory like there is in bank with the "deposit all".
Would be great for farming and skilling if you don't want to type how many items you want to drop with the "drop x".

I took this idea up with admins but they said it didn't feel safe if someone dropped something by mistake but I think that could be fixed with a setting to turn on or off drop all function, maybe if you turn "drop all" on it replaces the "drop x" with the function "drop all"?

What do you think?

I agree.  Pretty much every time I've used the "Drop X" function, I'm trying to drop all of that specific item in my inventory.  "Drop All" of that particular item would be much more useful to me.