If you will click on a location in Google Maps, you will find that most of the reviews have been posted for only one reason: The local guide level points.
These reviews do not help a person to get more information of the place. Eg. A nice place, good facilities, nice place to hangout etc. You will not get a clear picture about the location from these reviews.
A review should be alteast 200 characters long, should be descriptive and to the point. The review should be genuine.
Do not update your complaints. You can do it on another forum. Three main objectives must be set while writing the reviews.
1.) The review should help prospective visitors to decide whether they should visit the place.
2.) The review should highlight both the positive and negative points of the location.
3.) The review should be unique. Try to write about some facts which has not been mentioned by other local guides in their reviews.
The best time to write a review is the moment you have left the premises of your target location. Your memory will be fresh, and you will be able to achieve the objective no. 3.
Always remember that everything has a purpose. What is the use of a review which has no meaning?