I disagree that they always need more than weekly water changes. If heavily stocked, yes. Again, the ones at the shop I was running were breeding in the sales tanks with weekly 50% water changes and fed NLS exclusively. Although it is physically a single item food, it is mix of ingredients that provide complete and balanced nutrition and is healthier than a hodge podge of high protein frozen foods.
Everything I have said is based on my personal experience and the experiences of customers, clients, and other aquarium servicers I have talked to. I am not simply repeating what I have heard or read.
The breeder that I said had buckets of meds because his fish had problems on a regular basis did the aggressive daily water change schedule with RO that I am talking about. Another breeder I have talked to who does weekly water changes with tap water does not have those issues. It is very possible to have discus thrive with only weekly water changes.
I do not agree with the idea of high quality discus. To me a high quality discus is a healthy one that I enjoy, whether someone else likes it or not. The standards that are set for color, pattern, conformation, etc. are simply made up. People somewhere and some time decided that is how discus should look. I do not think this should determine which fish I choose to have in my personal tanks. I think other people should realize they have the option to do this as well.