Areas of concern
If you look at a reasonably complex page in edit mode in Magnolia 4, the sheer amount of edit bars and new paragraph bars can be overwhelming. Orientation and finding what you're looking becomes more and more difficult the more paragraphs you have. The areas of the page defined by the web designer or information architect to structure its content are no longer visible - they are hidden behind a cloud of bars.
Some paragraphs mainly exist to host or collect other paragraphs. These collection paragraphs - which usually have no or only very few fields on their own - are visually not easily distinguishable from paragraphs with actual content. As a result, it becomes unclear that you first have to add a collection paragraph before you're able to add any sub paragraph, e.g. you'll have to first add a new list collection paragraph before you can add a single news paragraph.
