Keeping wild caught fish in with domesticly raised fish is anything but playing russian roulete. Do things properly and you will be perfectly fine.
As to Wattley and Gabe, well first Wattley was a pioneer in the discus field, but since that time, many more advances and better ways of raising discus have come along. I also have several very very good sources that tell me since Gabe bought the wattley name, and since then the fish quality has been going down hill, I have no reason at all to doubt the information I have been getting from these people. Yet you say Wattley and Gabe are "partners" and you know them so well after all, too bad your not correct about the business end of that. Artificially raising discus is stupid to begin with. They should all be parent raised because it teaches valuable skills to the young. Of course we could breed them this way enough so that they become like angels and are almost incapable of raising their own young. EVERY world class breeder will let the parents raise the fry. If you want to argue this point I suggest you get hold of guys like Roy Khoo, Wayne Ng, Andrew Soh, Kelvin Chiang, Ivan Seah, David Lim, Chai Koon Seng, the Stendker family, Cary Strong, and the list could go on and on.
As to your angel fish plauge, that was in the 80s, time to move on and learn about the new things we have learned since then. Using an example like that is like saying treating heart conditions in the 80s is done exacatly the same as it is today. It is VERY easy to clean out wild fish now. With so many treatment options out there now that work very effectively and a much better understanding of diseases and parasites, there is no real arguement for not keeping wild fish now. Quarintine wilds like you would anything else and run them through the same deworming proceedures you would any other new fish and you'll be fine. Potassium Permagnate, Dylox, Panacur, Parzi, and Metro are just a few things you can use to effectively clean out fish. Your suggestion that wild fish are unsafe is false and unfounded. If you need other people to contact about cleaning out wild fish and their success rate I can give you some names of people in the business of Wild discus or ones that were doing it successfully, Oliver at Below Water, Al the owner of Simplydiscus.com and wilddiscus.com, and finally (a man who has bred wild heckles) Alberto from aquatechnics. Captive raised fish are no less of a risk of being infected with diseases or parasites than those caught in the wild, you never trust that a fish is clean and healthy no matter the source, doing so is one of the most unintellegent things you could do. For example, I know a reputable and well know person in the business who bought fish from another well known source, those fish that came from that source were infected with cryptobia, very nasty parasite that is virtually impossible to get rid of, only control is possible. Yet, there were no wilds anywhere near those fish, all were domestically raised. Yet you contradict yourself by saying you kept wilds in with domestics...hmmmm and even did domestic wild crosses, I thought we shouldn't be keeping wilds with domestics though?
Ahhhh finally, why are raising quality discus so much harder than other cichlids. 1) Food, 2) water quality. You can raise discus much in the way you would other fry, but you won't end up with a high quality fish. They will not grow fast, they will not have a good body shape, they will not be top notch fish. First the food, like many fry, they need BBS as their first food, not uncommon, next comes what you should be feeding them to keep them growing, you can't buy this stuff either, or anything that would come close to the quality. 50-50% mix of Beef Heart and Shrimp. Multivitamin supplementation, Calcium and Vitamin D supplementation, Egg yolk, amino acids, spirulina, rotifers. So first, you have to make that food, and use it as a staple diet. Need to do that for other cichlid fry, don't think so, but let me go on. Next, is the feeding frequency, to maintain proper groth rates feeding should be done every 3hrs. 5-6 times daily, generally from 7am till midnight. Need to do that for other cichlid fry, nope. Next water quality, anything but the best is not enough. One 90-100% water change done daily is a bare minimum, better would be 2 or I know some breeders will do 3 100% water changes daily. The cleaner the water the quicker the growth, the better the fish will be as well as healthier. Again, not something you need to do for other cichlid fry, but is really nessecary for discus fry. Another factor to water quality is the need to clean filters daily, and wipe the glass on the tank down every day to remove any kind of algae or bacteria growing on the walls.
I know my information is correct and I can confirm it with numerous other people who are making a living selling discus. Much of your "information" is very incorrect from all I have learned. I suggest you pick up a book that just came out and take a new course on discus, its written by Andrew Soh and called "Discus the naked truth". Andrew is a grand champion breeder and divulges a lot of info in this book that is not common knowledge, though you probably would discount his expirience anyhow.
I still maintain that if you want good information about all that is discus, do not take the words of people on here, go to sites dedicated to those fish,
http://www.discusasahobby.com is the best in my opinion I post frequently there and can say for a fact that the people that know these fish are there.
I appreciate the advice, and I've already checked out the discus specific sites. It's just that I was afraid to post there b/c I thought I'd be attacked for wanting to get into the hobby. Do you know what you're getting into? Do you know what you're doing? Are you prepared? Yes, yes, yes 
