It would appear that Google is now allowing users with just a Google account to leave a review. The account can be either gmail or non gmail based. The only requirement being that they also leave use a first and last name but the requirement to have a full G+ account is now gone.
First spotted by Conrad O’Connell (h/t David Mihm) the feature seems to be live for both mobile and desktop users.
The separation of Google Local from Google Plus has been long and painful and this update is one of the last steps to make the separation complete. In doing so, Google reviews should be somewhat easier to leave going forward. Simultaneously with this update, Google seems to have fixed a long standing bug that prevented reviews being left on mobile browsers if the business had no previous reviews.
Easier Google Reviews
The new login system only requires any Google account and name for a user to leave a review:
And the view from the desktop