It would be great if I could make custom layouts more usable by arranging fields into groups or sections with a clearly visible heading. As it is today, work items have a long list of fields that are hard to use. There's a lot of cognitive load happening to find what I need whereas better organization of fields could really help and allow for expanding and collapsing of information.
The status of this idea was out of date. Since this was requested, we have added the ability to organize fields into custom tabs. Checkout this blog post for more details.