Also the visuals can be misunderstood to be communicating something - e.g. the dirty walls - does that mean my city is bad in some way? Is crime increasing or is the wall being stained by pollution?

You can't just make stuff 'look nice' without affecting how the player behaves

Part of the author's point is that the way the city "feels" is not just part of the game but, for them and for a subset of other players, a key part of the game. We're talking about how to make a city simulator have more verisimilitude with the cities you are simulating!

But if you miss the trees for the forest it's bad too. I wouldn't want a building to be represented by a box that says (office) even if it made for a better simulation. Nevermind I just remembered how much time I soent playing dwarf fortress.

I had an argument at one point, honest!

Also, it's very much a matter of taste. I like the pristine look. I have real life if I want to see dingy, worn down buildings and yards. I don't want that in my fantasy city.

A city builder is a lot of different things to a lot of people. Some people want to feel like their creation is “alive,” and varying degrees of wear and tear can achieve that. It makes the city feel lived in. I wouldn’t say it’s my highest priority but I’d say it’s definitely a valid one.