The ongoing dispute regarding the necessity of seeing an adequate number of courses by an architect in order to properly evaluate his body of work is important. It is not limited to criticism of GCA. Certainly, if one wishes to rank the work of a prolific film director, the critic would better be served if he viewed as many works as possible. Similarly, literary critcs benefit from the same exposure. That is why there exist professional critics; they have the time to do the "homework" as Matt Ward puts it.
However, it is a more difficult task when it comes to evaluating golf courses because of the time and expense needed to go and see courses which are spread all over the world. Thus there are fewer individuals who have the ability to see the requisite samples.
I note that this does not keep any individual from making a perceptive review of a course. If that review exposes weaknesses in the architect's work and other reviews of other courses suggest a similar weakness, then a reader might fairly conclude that the weakness is habitual and characteristic of the architect. Accordingly, a series of reviews by mutiple critics may be as telling as the review of a single more travelled critic; indeed that method likely filters out any bias that may be held by the single reviewer.
Finally, I suggest that , in the end, the analytical ability and taste of the reviewer is of critical importance. This may be a matter of the reader's taste, but a critic who has seen 100's of courses but doesn't "get it" won't provide better information than one who is less experienced but has a better understanding of what makes a course "great'.