A better way to do this is to see how many asterisks each got, not on a scale of 1-10. For example, 2013 Wimbledon can have an asterisk for Nadal's early loss, Fed's early loss, and one asterisk for all the retirements/withdrawals to give it 3 asterisks (could have more, but didn't want to look into it).
That is a good idea.
You should create a separate thread on that for this year’s AO. I can already count 4 *s already. One for Nadal’s back, one for the heat, one for Djokovic’s clownish volley on MP vs. Wawrinka, one for blisters…