Could you give me an example of help that you used to use that you can no longer find? There has been some reorganizing, and some changes, but if something that was useful is now gone I'd like to know.
While the look and feel of the page has changed, the contents are still there. Now, instead of a more nested table of contents, there are two tables of contents: one for the author of a map, the other for the user of the app. On the page you are redirected to, http://doc.arcgis.com/en/collector/, see the help content by clicking on the "Create maps" or "Collect data" tabs in the blue bar along the top.