It'd be nice if you could set up "item snap" spots in your world where placing an item on or near that point would have it snap to a specific position/rotation/scale set by the world.
For example, a driving world where you could spawn in a custom car model as an item. Assuming items aren't allowed to have Udon or other methods of custom code on them (meaning the car couldn't have an inbuilt driving system), this would be a handy way for the world to align a world-based driving system to the custom car model.
It's hard to suggest ideas for items when we don't know what all they're capable of, but a method for worlds to control item placement other than a global on/off toggle would be very handy.