I was making a crusades template the other day using the map 'AD 1045: Roads of Silk and Iron' (LINK: https://www.warlight.net/Map/24311-AD-1045-Roads-Silk-Iron
) and was designing the border between Mongolia and the Chinese states (which start out at war) when I thought it could be a cool idea to build a Great Wall through neutrals, giving the neutral territories more troops than the surrounding ones and giving a buffer to China. Then it came to mind that this would disrupt some Chinese bonuses and how I wished players could simply add the Great Wall themselves as needed. I arrived at the idea of being able to give certain slots more cards than others, so I could give the Chinese players blockade cards that the Holy Roman Empire didn't have.
This could also be applied to other types of diplos, such as a World War Two diplomacy where Germany receives a lot of air lift cards and Poland does not in order to represent the German technological superiority. Or maybe even a colonial diplomacy where the British Empire could use air lifts to represent naval superiority.