Clear visual distinction: empty parameter fields/cells VS multi values.
It happens sometimes in a rush that multiple instance values get overwritten by mistake. When a parameter contains multi values it looks like its empty, while it’s not true. Experienced Revit user are aware of the power and risks of changing instance parameters, but starters not yet. It would help all users and give a more professional interface if fields/cells are able to indicate clear the fact it contains multiple values.
Please give us under File>Options>User interface … the option how "multi values fields" should be presented, by filling in/modify a text field (depending of language, text font, field/cell color, …) and checkboxes to activate this function on Property display and/or schedules.