I've been working on a Spur for Hireling Traits and in doing so noticing some features about designing for Roll All the Dice charts.
First, the d4 and d20 are useful bookends; whichever category has the most options needs to fit within 20 and the d4 helps you think of the overall theme in the most abstract way: what four chunks can it be broken down into?
Second, the middle dice are all nicely within 2 of each other. What this meant for me is that I would often have to bump a category up a die and then rack my brain for two more listings. It could work the other way too; if you have to bump down a die, really strain your brain to consolidate two of the entries. Here the format becomes a generating tool.
Finally and most interesting to me, some features of the dice can really aid the DM in reading the results quickly. I noticed this when I changed the distance category in my Encounters spur away from a simple die result x 100 feet. So, I consciously tried to keep this in mind with the Hirelings Traits spur-- for example the d6 is age in decades, and, in general, lower numbers mean less, higher more.