It would be really helpful if we could get the following warnings:
When copying an item, if the workset of the new item is different than the old. This is usually a mistake
If the item you just placed is invisible, and that is because the workset you're currently on is turned off in this view, then Revit should warn you directly about that: "The workset you are on is not visible in this view", rather than the generic something is wrong warning.
Ideally Revit would know which worksets everything should be in. If you place a light in a power workset, or a pipe in a ductwork workset, Revit should know. To do that Revit would have to add something to each workset like "default workset for conduits", etc. This is a big ask I think.
More generally, there seems to be some trepidation on the use of worksets. Please share your feelings on that.