If I'm running a module, it's because I'm interested in the story and actively want the assistance of not having to come up the framework from whole cloth. So, the bare minimum I'm looking for is a writeup for what happens if the antagonist/conflict of the module is directly confronted, and prevented from executing their plans/happening. I'm not necessarily looking for a specific how to do that in there. To me, it then seems obvious to include the converse, what happens if they are not stymied. I may end up coming up with my own ending, but only if I'm dissatisfied with what's written.
On a tonal level, I'm not looking for a specific moral guideline. More important to me is the existence of an ending that concludes the story with the party feeling like heroes, and that they succeeded in their goals. Unless the adventure is very specifically a bleak one, where winning is more avoiding the worst than getting the best (and there's definitely room for that sort of book, but I'm not likely to reach for it quickly), I want a path to at least exist where the players don't feel like their win is inherently compromised. I'm not saying I need that to be easy, or the default conclusion, but if the party did all they could be expected to, I want everyone to walk away from the table with a satisfactory, if perhaps sometimes very traditional, narrative arc.
That all said, if the book goes out of its way to think about the gradient of success, or has a couple different paths that are plausible given expected approaches, I'll definitely appreciate it more.
I think there's room for certain adventures to directly concern themselves with morality, and how the party specifically approaches and achieves their goals, but that's the sort of thing that requires consideration from the start of the writing process, a consistent thematic approach throughout the entirety if it. And, given the variability of morality in the context of this system, there's a very reasonable chance that the DM/party could find themselves disagreeing with how the author landed.