What happend to the "Down Arrow" on the back button so I can go back several pages or back to the Google Search with one click?

You can get the drop down list by either right-clicking on the back/forward buttons, or holding down the left button until the list appears. If you want the drop-down arrow you can add it with the Back/forward dropmarker add-on - https://addons.mozilla.org/firefox/addon/backforward-dropmarker