As a Roblox developer, it is currently too hard to overwrite multiple places. The use case may be niche, but it would certainly make uploading places into a game much easier. For instance, two of my games use a technique where they change a few key things based on the placeId (such as difficulty or which map to load permanently.) However, as it currently stands, I have to upload them one at a time, which can take a while, depending on how busy the Roblox servers currently are.
If Roblox is able to address this issue, it would improve my development experience because I could just queue up a local project to be uploaded to all the places I want it to overwrite all at once, and let it do its thing.