It would be nice for there to be a full indicator when stacking planks on the pallets and a limitation of dropping planks when you have reached the limit. Currently when you have fully stacked a pallet, the planks continue to drop onto the pallet but are not 'stacked' and will move around/despawn.

good idea,  like your inventory is full type indicator.   I don't think it should stop you from placing them on top though, i tend to drop the extra on top of a full pallet and let them sit while i gather the components to build a new pallet.