"Back to Pages" link
...can the Back to Pages link on page edit become a plain 'old <a> instead of a postback control?
You can contrast this functionality with the browser's Back button. If you click Back or hit backspace while in page editor, you receive a message informing you that all the changes you have made will apply but the page will be locked unless you unlock it or an admin does. Essentially the back button acts like a link to Sitefinity/Pages.
In order to remove the Back to Pages button you need to alter the backend theme and that is not advisable as when you do you may lose some of the widgets that are not available in the menu. For example if the page editor widget does not migrate to a content placeholder to one with a different ID it will not be visible. Information on how to change your backend theme can be found here.