I would argue treating it as a dungeon rather than as a wilderness -- come to think of it, I treat wildernesses as dungeons too. When you're mapping the city, think of each neighborhood, district, or quarter as conceptually equivalent of a room in a dungeon. There are one or more ways in and out. There's a block of descriptive text you read to the players when they first enter the area. There may be bad guys waiting there, or an NPC encounter. There may be hidden stuff you have to actively search for to discover. There may be several skill challenges available that each lead to an opportunity or reward if passed. Without this conceptual rigor, everything tends to feel the same for me and for the players.
I would never think about mapping every single dwelling, any more than I'd write a life story for each goblin in the mob that the PCs are about to hack through. Just a representative building layout or two, and leave the mapping to major structures like monuments, fortifications, marketplaces, and so on.