In the story I'm writing, the protagonist writes a representational story about himself and about the fulfillment of his wish impossible in his reality. Such wish is the sub-protagonist's main goal, and it's set still at the beginning, and the rest of the story is just the sub-protagonist's journey to accomplish it. And that's it, no gotchas.
However, I'm not sure if it'll be a good idea to leave it so predictable and unsurprising. I mean, of course that achieving such goal have some conditions he has to endure, but in the end, his goal is still accomplished, no matter what, and he knows such conditions since the beginning and goes into the journey with that in mind.
From what I know from the other works I use as reference, when there's a solid goal since the beginning, taking the whole story to be achieved, there's always a plot twist (usually several) affecting such goal, and in the end, the goal is achieved, but in a way never known before in the story, and a lot changes after those twists. But in my case, I can't do much, as the sub-story is the protagonist's wish fulfillment, and it would make no sense for him to make the sub-protagonist fail in his journey, and the reader would read all the story just to find out that the sub-protagonist fails.
So my question is: is it always necessary for a story to have plot twists to be considered a good story? Or a story without them has to be executed with great mastery to not get bad impressions?