Designer: More efficient use of screen space, especially when editing expressions

The Designer UI is quite good in terms of simplicity and ease of use. Yet when working on flows wich are a little more complex, a developer wishes to have a little more efficient UI. 

The expression field is always one line in a fixed width. When working with data structures with one or two levels, the expression field is already filled up completely with the first variable. For everything else you would need to scroll (which often does not work well, see reference support ticket). 
It would be good if you could enlarge the expression field when you need to edit more complex expressions.

Also, the visual flow always takes half of the screen. When editing a node, all of the node properties are in a vertical list in the bottom half of the screen. Now I have to scroll in the bottom half, when most of the top screen is unused. There is already the feature to bring the panel to the right, but it would be good if you could move the middle screen divider up or down to decide which proportions are best for your editing.

When using the "test action" to execute a HTTP call for example, the test results field is only very small on the right hand side. If your API delivers some complex data structure, or maye an exception, you cannot use the test results screen efficiently at all. You would need to copy the contents to an external editor.