LiliArch

Imagine realizing that a planned story feature is impossible with the planned rules of the world. Good thing is that the whole thing is still in its design stage, so changing things isn’t TOO difficult, but I’m curious as to what people think.

(My personal stance is that the best course of action is to change the thing that is less important to the whole.)

Universe building or world building is secondary to primary story. If your primary idea and theme of the story is in the story, and not the story world, then you should adjust the world, or vice versa. In other words, which is idea/concept is dominant, pick that one. 

Something else to consider is how elaborate each one is, the more work into one idea might justify priority over the other. 

My suggestion is to pull ideas for the story from the story world rather than forcing the story world to adapt to whatever narrative you're writing.

If your story is so rigid that it requires the lore to explain it, then it may be better to evaluate whether that story may need revisions. Inversely, some worldbuilding elements could be removed if they're interfering with the tone or purpose of the narrative you're writing.

Essentially, use all of the elements you create for the lore in the story and draw inspiration for how to enhance that story from the world as you build it.

For example: The location requires hovercraft to get to the destination; now your characters can have a moment to interact as they're stranded when the hovercraft inevitably breaks.