Sorry if this has been proposed before, but I thought a simple way to fix most forms of walling is to allow quests like greet, deliver item, consult and such to be able to be completed in the same distance range as current emote-quests.
Emote quests dont care about walls and can be done from distance, those who want to take the extra effort to protect their questgiver can do so, without being able to block everyone else from this progression. Especially annoying for far-away nomad quests of which you have no way knowing you are traveling for nothing..
Ideas regarding this? For the item deliver just make it act as if item is given to tree from distance, making it dissappear from inventory over walls and such too..