Using Visual Editor for UIs, Views, etc.

Visual Editor in Eclipse works great to build new composite components.

But, when I’m building my UI, I most often need to simply combine existing components to create a view. Unfortunately, Visual Editor
requires
that we build a CustomComponent and cannot work directly on a layout, UI, View etc.

Is there a reason why it cannot directly build on any type of root layout?
As a workaround, I could make everything I want to design visually, a CustomComponent - but that seems like hack. A component is intended to be reusable, while a layout can be any one-off design or view.

What’s the recommended way of visually building views with Vaadin?

Regards Philipp