A problem I've seen with CGC is that they do not advise submitters on their submissions. Granted, most comic collectors are knowledgeable enough to know what they are submitting and the approximate grade. However, from my observations of onsite submitting, quite a few people literally have no clue what they submitting.
I have seen guys submit mid-low grade modern non-key issues, in which they pay more in grading fees than the value of comic being graded. Some of these are indeed sentimental copies, but others just don't know what CGC is about.
I understand CGC is a business out to make money, but they are not in the business of screwing customers. I feel they should at least ensure that the submitter is aware of the pitfalls of submitting (i.e. qualified, restored, etc.)