Is that actually illegal or just against the rules? I would expect it would be perfectly legal to start your own, although I could see why people might object if you don't at least limit it to make sure it stays at safe levels. And if you do limit it, you'll have all those advantages you said, but not the obvious one of not having cheaters. It's just as hard to tell if someone's doping more than they should as it is to tell if they're doing it at all.