Luckily, I did not have to fight for my approval, however I know many who have. They have had to fight for years. 7 is the longest I am aware of. Personally.
SSA Should develop a self service portal which allows applicants a timeline and step view of their claim starting at day 1.
It should track and count down the typical number of days till completion. If the issue is held up in a particular department there should be self help links to electronically dispute, file, notify the appropriate department as well as have each application movement logged in the Applicants account.
To help bigger issues such as appeals, more public input from advocacy agencies would be helpful in keeping a persons money in their own wallet, as they are living off loved ones while they wait and should be able to receive all of their benefits owed.