@H 1 L D A
"places where certain pieces of content (Arch, paying death costs, presumably Necromancy, opting in and out of PvP, etc.) are given a tutorial or at the very least a brief explanation of some kind."
Wildyness is not instanced regardless you opt in or out of pvp. It is the same communal place for every players. Same with Necromancy. We have not been shown to have anything to opt in or out in City of Um, so no. It is most definitely not instanced. We all go in with nothing and we all unlock content and populate the city with quests among other new content, much like how we all progress in one communal strike in Fort Forinthry, which is not instanced at all and nothing to opt in or out of.
@Deltaslug
I am 100% sure City of Um will have its own narrative that sets itself apart from Ashdale, Burthorpe and other new tutorial places, and this is a very good thing. Um is only empty in day 1 in term of personal content, but we are all going to see new players left and right just like what we see them left and right in Fort Forinthry. We can all interact with each other regardless what our progress in the story mode is. We can all share what we have and team up for ongoing adventures. We can all in the "New Player Guild" to share our communal experiences regarding how far we have progressed in Necromancy and the game perhaps as long as we never graduate from such a guild.