Recently I had to create a few Content Types with many fields for testing purposes. When i was doing it, I realised how uncomfortable it is, when Content Type is growing:

• You have to scroll all page up and down
• When you scroll, you don't exactly see, where one field definition ends and another starts
• You have to scroll through definitions already set, and you are not interested in they in most cases

I came up with an idea

• every field can be a simple section with header
• clicking on header toggle visibility of section by expand/collapse,
  In this way we don't have to see field definition that we already set if we dont want to.