It just seems it's too easy to gain certification. A ton of superintendents are certified. And on the other hand there are a ton without that get compensated very well and are excellent superintendents. At least they get the free luncheon at the GIS every year! 
There is another 75% of the superintendents out there who have not been certified.
A ton? How many CGCS' are there? 25% of
Class A supers...not 25% of all supers. How many Class A supers are there?
The portfolio is not the same as one you would prepare for a job interview...it is intensive, covers a multitude of areas one needs to be competent in, and requires written documentation across multiple skill sets...yes it is time consuming, but it is not "easy".
The bar was raised a few years ago, when it became tougher to become a Class A...therefore tougher to qualify to even apply to become a CGCS. And the certification process was revamped as well; it became a much more intensive process, instead of the former process which involved being a super for x years and passing an open book exam (not to say in any way that that was easy). The GCSAA spent considerable time and effort revamping the process to assure that those professionals in the organization that chose to do it and succeeded would be achieving the highest designation and be recognized for doing so. Many other professional organizations have certification programs, and when GCSAA revamped theirs, an outside consulting firm concluded that this new program was a very demanding program compared to other professional organizations...sorry I don't have the exact references...
In any event, it should be a personal choice as it always has been; I know many supers that I look up to and respect and some are CGCS', some are not...