I would love it if we were able to remove Legends from sheets, without either doing it one sheet at a time or deleting the legend entirely. Would be great if you could right-click on the Legend in the browser and have a 'Remove from all sheets' option. (I know you could just 'duplicate with detailing' the Legend first and then delete it but that's a bit of a fudge).
Taking it a step further, it would be even better if there was a way to add/remove Legends to/from multiple, specified sheets in one go, and not necessarily all sheets. For example, I have a project with 3 phases, the 1st of which has gone for construction. I had to manually remove my 'Not For Construction' stamp (which is a Legend) from 60+ drawings, leaving it in place on the other 100 or so. This would have saved quite a bit of time. How the positioning would work for the adding, though, I don't know!