The piece by piece system is excellent, but it would be even better if we also had the click and drag system for walls and paths just like the road system in Cities Skylines for example. And more than making long straight walls very fast, we could also click and drag circular walls by adjusting the circle again just like CS.
Allowing us to make perfect small or big circular buildings or regular wavy walls like in the pic below,
Thus letting us choose the exact shape and size of any building,
Then allowing us to create big circular pieces, rotate them, and place them the way we want,
And also make smooth fences or hedges that would perfectly fit to paths or roofs,
I might be a bit idealistic in my propositions but I feel like such a tool would completely change the way we build in the game, by combinating the piece by piece system to some "hand made" personnalized shapes.
Allowing us to make perfect small or big circular buildings or regular wavy walls like in the pic below,

Thus letting us choose the exact shape and size of any building,

Then allowing us to create big circular pieces, rotate them, and place them the way we want,

And also make smooth fences or hedges that would perfectly fit to paths or roofs,

I might be a bit idealistic in my propositions but I feel like such a tool would completely change the way we build in the game, by combinating the piece by piece system to some "hand made" personnalized shapes.