i'm kinda leaning towards both, maybe one half built like a little village and the other half more like a park/forest, but it will definitely depend on the map!
It's likely that at the start I'm just going to end up putting stuff down wherever I think it looks nice, but once I get further into the game and have access to a lot of furniture, I'm either going to make a fairy-tale or traditional looking island. Or maybe I'll try to pick a theme that matches what the exterior of my villager's houses look like. I'm not sure, there's just so much potential that picking one theme seems impossible!