Page Up/Page Down
A really cool feature to have in Revit would be a Page Up/Down button while working on sheets. If say you're on A-100 and really deep into the Families section of the Project Browser. Instead of having to scroll all the way back up to Sheets, you could instead click Page Down and it would open A-101 (or whatever the next sheet is in the browser). Or additionally, if there was a drop-down that opened and allowed you to pick a sheet to open. So many times I've found myself asking "why isn't there a Page Down button?"