Many oral steroids are just that - a form of "drinkable testosterone" in tablet form. (Yes yes, I know its not test anymore, its a new lab engineered molecule, but its designed to supplement the action(s) of naturaly hormones.)
Yes, you can create all kinds of molecules with anabolic and androgenic proporties that are not available on the market. But its far to expensive to be of any value, not to mention out of the numerous such compounds known, medical science has boiled what it needs down to those compounds that are available. Why do you think this is? Cost and effectivness weighed together. Their may be some super compound out their that would be perfect for bodybuilders, who knows. I think we should be plenty happy with what we have. My only wish, were I to design a "new" steroid would be one that was absolutely free of side effect.