I learned something this summer by reading their 2016 directory - KOA currently has four classes or categories of campgrounds. They are "evolving many of our locations" into the first three:
Journey - not fancy, for overnighters, has 50 amp pull-thrus, well-lit after-hours checkin.
Holiday - more amenities like patio sites, deluxe cabins, and meeting rooms.
Resort - Fanciest and of course more expensive.
These categories promise certain things, and the CG owners apparently agree to go with the gameplan.
However, if you read between the lines, there is a fourth group which is None of the Above. I guess these owners are not yet, maybe never, signing on to whatever standards are being imposed. Or maybe it will take time to change their facilities to conform.
I've stayed in some so-so KOAs I wouldn't recommend and, sure enough, they were not identified with a badge in the directory book...not part of the three groups. I'm going to avoid such CGs in favor of Good Sam and Passport America - why pay a premium?
We stayed at Quechee Pine Valley, Vermont this summer ("Holiday" class) and it was great. Also stayed at one of the "Journey" locations for an overnighter and had great service.
I'm guessing the KOA organization has known for a long time that their product quality varies tremendously and can be a real turn-off. So maybe they are trying to differentiate what you're likely to find.