It is very nice that when using the "copy" feature in this window, one can then in a second contact sheet open an entirely different file which may even be located within an entirely different folder or drive and then use the "Paste" feature to replace the metadata in the new file. [Some would expect that when going to a new location a new blank Keyword(IPTC) would open]. I often use this feature between different folders, while also simultaneously using the OS's "Copy/Paste" function for a specific part of that Metadata that I want to change in the target file.
So, my feedback is: Don't change that feature since the "Clear" button is always there for people who want to start with a fresh Keyword(IPTC) window.
Thanks. I'll pass this along. We have no plans to change it.