1 >> This should be urgently fixed by testing the media uploader in different types of servers, browsers and configurations.
2 >> if I'm using a big layout on my blog, why will WP limit all images to 500px max width, and especially why does a user have to search the forum to find out he has to manually change WP files to set a new max width? This should really be a dashboard function.
3 >> When posting full size images why does the image still link to a new page that shows the exact same image? This should also be a media uploader function (weather or not the image links to new page/tab)
4 >> When uploading media you have to always check if you prefer thumbnail, medium or full size. There should really be an option so the uploader remembers user preferred image size.
I really hope the media uploader is quickly improved, flash per si adds nothing but a bunch of compatibility, safety and code issues.