I think the mirror is way overdue for a major update so I kind of have a few ideas
I would love to have the ability to change the width and height separately sm so you can have different sized mirrors for different areas
Another thing I had the idea for which comes from VR chat is the ability to have a PNG mirror where it only shows players
I also you do hope for the ability to turn off the mirror unsynced, because I could do something that is also in VR chat where I can have multiple mirrors around the map for different areas.