Turned out to be much worse based on what evidence? All three of your examples have been in use for over a century and there have been dozens of pain killers invented since then that are much better at targeting specific pain receptors without the addiction.

I should clarify I'm supposing that by opioid they mean morphine based opioids.

You should probably read the article. It's not morphine based.

It is targeting mu opioid receptors, mentioned in the article as "morphine receptor."

It may not contain morphine, chemically, but neither does oxymorphone, it's only similar.. the only drug mentioned that actually contains morphine, ie. is morphine based is heroin. But having side chains and other additions can totally change a drugs' effects. Morphine-based is a poor distinction.