Requirements can be measured as good or bad based on requirement attributes.  Often our perception of requirements is just that, a perception.  Good requirements have specific attributes which can, fairly easily, be measured.

If you find you do not have good requirements and the culture of your organization does not allow you to gather them…. Then that is simply a reality you must work within; however, you should not allow yourself to be disillusioned to what the quality of your requirements is or software will be.

Knowing the actual quality of your requirements will help you to predict the quality of the software you will deliver.  Many aspects of quality in software are completely out of your hands. They are directly linked to the quality of your requirements.  Knowing this will help you set expectations of quality and schedule performance.  Depending on your organization, you may not be able to share your findings fairly as the organization might not want to confront the culture as affecting quality, cost, or schedule but the truth is that more than skill, culture drives these factors…

The following is an excellent article which describes good requirement attributes followed by examples of requirements which have been corrected and an explanation of why they were deficient.