If something is more potent than morphine it doesn't mean a thing on its own. Bioavalability, can it easily cross blood brain barier, how it interacts with other alkaloids, is it full or partial agonist, mechanism of opioid action (G-protein-coupled vs beta arestin)...there are many known and much unknown things that contribute to effect of some substance. Especially if we are talking about plant and not a single molecule. Pregabalin is a single molecule but it is still a mystery to a great degree even to those who tweaked it. I love kratom, and believe that it contaons alkalods that act as opioid agonist, partial agonists and antagonists. It sure can't hold a candle to classical opium poppy derived opioids, but exactly of that built in mechanism regarding opioid effects and complexity of the other effects (adrenergic, serotonergic, dopaminergic...) it is a great tool for multiple things.