While the current highlight and ’priority settings allows some visual “grouping” of items, I’d like to suggest the replacement of highlighting with the ability to color Text and Text Background. This is a more capable system of indicating items than a single highlight color.
As a bonus, text color/text background color gives the ability to use text as a more useful version of headers. While the existing headers (different text sizes) are fine for large screens, they are less useful on smaller screen devices, i.e. phones & tablets, where screen real estate is at a premium. Colored text/backgrounds allow for a ‘visual grouping/focus method’ that does not require more screen space.