The Missing Revert Layout
One feature I miss about QPS classic is "revert layout." You could always make an earlier version of a layout the current one. We rarely needed this command, often because the current layout was corrupted, but it was handy to have. There was also a "revert article" command that was helpful to writers and editors.
In both cases in K4 you need to use View History from the query panel and open an earlier version as a read only document. Then cut and paste between the old version and the current one. Or move pages. In InCopy this isn't too bad but in InDesign you have to unlink and relink articles. Can get messy.