The Cross-wiki upload is often used for uploading pictures that aren't the uploaders own work.
Users don't know how files are stored on Wikipedia (they think it's Wikipedia but it's Wikimedia Commons!). They think the file becomes part of the page as in a word processor.
I suggest to inform people using the cross-wiki upload the first time about where files are uploaded to and ask them every time whether it's their own work or not. No normal user (or an "average Joe") clicks a link and visits another page in order to upload a file. Many users ignore the text next to such checkboxes like "This is my own work" or "Agree to our terms of use", some even don't read it. When a user has to choose whether the file is the users own work or not, he/she can't just ignore it because a decision has to be made. Because "This is not my own work" has many possible options, the upload wizard has to be used. Therefore the upload wizard has to open in a new browser tab with the file already uploaded in the cross-wiki upload tool and the "Release rights" tab open. The steps "Learn" and "Upload" should not be displayed. Once the upload is completed the user is asked to go back and click a "continue" button to make the editor loading the picture and opening the final "Media settings" window.
Even if the picture is the user's own work the uploader might not want to use the Creative Commons Attribution-ShareAlike 4.0 license but another of the five licenses available in the upload wizard this should also be possible using the cross-wiki upload feature. I've never used that feature because I've always either improved and re-uploaded a picture or "bulk-uploaded" my pictures using the upload wizard but it's actually not possible for me to use cross-wiki upload to upload my own work because I want to release my pictures in the "public domain" (this isn't really possible for German people like me, but I can do the same) by using the license "Creative Commons CC0 1.0 Universal Public Domain Dedication". To enable users to use the license of ther choise the newly added page should also enablethe user to choose one of those five licenses.
I haven't found any page for feedback about the cross-wiki upload so I had to write it here. I hope you'll understand what I've written and meant. If there's a better place for this suggestion, please move it there or ask me to do it.