To qualify to be a Good Sam park, the park must meet minimum scores on the scorecard that is published in the Good Sam Directory. You can use the checklist to validate the scores yourself. What you won't find is a score for how fast phone calls are returned or a requirement for the office staff to be able to authorize anything. Each Good Sam park is independently owned and the owner is free to have any policies they wish, as long as they don't violate any law.
You say you used to stay in the park and it wasn't crowded. Now it is over crowded. Unless in the last year they jammed a site in between each site, that would indicate the new owners have increased business, which is what I am sure they were hoping to do. Occupancy varies at most parks throughout the year. Are you sure the visit when it wasn't crowded wasn't during the slow season and your recent visit was prime season?