Avatar and the like featured a moral dilemma, of sorts. Insurrection featured a gradually unraveling mystery that at first appeared to be a moral dilemma, providing pros and cons: mystery is always "more" (and probably "better") than no mystery, but when it removes the moral dilemma, it may end up being "less".
Unless the moral dilemma is replaced with a great action scene, of course. Many successful movies are based on this. Although they may skip the mystery phase. And sometimes also the moral dilemma.