Google announced they have added three improvements to the Google Webmaster Tools verification system.
View Verification Methods
Now, you can not only see who the verified users on your sites are, but the verification method they used to achieve that status. Where appropriate, the verification details will have links to the correct URL on your site where the verification can be found.
Here is a screen shot:
Removing Verifications Method Prior To Un-verifying Users
You simply cannot just delete a verified user without deleting or removing their verification method first. You now need to remove the verification method from your site before un-verifying an owner from Webmaster Tools. Now, Webmaster Tools will check the method that the owner used to verify ownership of the site, and will show an error message if the verification is still found.
Here is an example of an error message:
Shorter CNAME Strings
Now, when you use the CNAME verification method, the string is shorter. Google did this to support a larger number of DNS providers. Note, existing CNAME verifications will continue to be valid.