One of my big goals is to attempt to be more creative with my town design. In all prior games, including New Leaf, I never spent much time customizing the town with patterns and so on. I have more or less played every game as if it were the GameCube game and kept a very under-developed (with the exception of PWPs), forest-feeling town because it has been my personal preference. An additional reason for doing this though is that even in New Leaf I felt rather constrained in what I could accomplish, and anything I tried never looked as good as just letting life happen and seeing what the town turns in to over time.
In New Horizons I think my attitude will shift a lot more toward customization of the landscape because of the outdoor furniture. The outdoor furniture adds such a complex level of customizability that will be impossible to resist. Additionally, the ability to round off the corners of paths (and presumably, patterns), will make customization all the more enjoyable. If we can truly place houses wherever we want as well, then it will be hard for me to resist giving the town a realistic "planned city" type feel.