Ah - you'd like the module author to handle more of the "what-ifs". Yes, if done fully that would make most adventure modules 10x longer than they are now - which while good in one way would be bad in another in that the core useful info would get buried under mountains of corner-case what-if examples.
That said, I can think of many modules where the author's take on a few very obvious what-ifs would have been greatly appreciated!
As for success-failure flow charts, that's something I can see as useful in theory but not so useful in practice, as no two groups are going to deal with any given success or failure the same way.
I use modules in part because they do a lot of the busy-work for me: the mapping, the monster/opponent generation, etc. All I have to worry about is bespoke tweaking to suit my own campaign (e.g. conversion if needed, or reskinning monsters to suit my setting) and filling in any needed backstory. Even with that a module still cuts my prep work by at least 75%.