Piotr Nalepa We are using blocks to organize content, because specific behaviors are needed (drag & drop) for customization. These blocks need more separation than what a regular amount of internal whitespace can provide. The limit shouldn't be only the internal whitespace (padding), but the lines/dividers that define blocks limits and some external margin. As you know, these blocks inherit grid rules (this happens also with content cards, for instance). Maybe we need to reduce the amount of padding. In any case whitespace should always be our ally, not our enemy
The reason behind this is that well-defined blocks structure content into easily-digestible chunks, each of which should be understandable at a glance. If you check UI patterns for drag & drop interactions there is always enough whitespace among blocks. When the user sees a page sectioned neatly into chunks, her eye is guided along the page more comfortably. This is something that the human visual system always looks for, it looks for bigger patterns, wether they are deliberately or not. We need to reinforce the former, in order to increase user’s experience making simple tasks as simple as possible. Hence, having a clean and consistent page structure assists the user in ease and predictability of her navigation.