Whenever we add or change a column on a Content Type which inherits from Document Set, we have to manually adjust the Site Columns we want to display on the welcome page. If we want to add a column near the top of the welcome page, that means removing everything else, adding the new column, then adding all the previous columns back. This is tedious as we iterate through the information architecture.

Ideally we should be able to drag and drop columns into the right order whenever we need to make adjustments. (The configuration UI could be improved by adding drag and drop in many places like this.)