This is my idea for commenting:
Only having to enter your MySpace (or Friendster, Facebook..) username and password to comment. Your gravatar will be small version of your MySpace picture.
Comment will appear under your username and wil link to your MySpace account.
Should be possible, I visited a website the other day (wasn't WP), but it allowed login with your Friendster account.
I think it's good because it will illiminate having to create new accounts every time you want to join a new site, and will improve reliability.