With the addition of a new character named Mr. Magic in my The Sentinels series, where magic is a prevalent force/ plot element. He is a character who's pretty well versed in the mystic arts and I realized "oh crap, I haven't mapped this crap out yet!" So for the last 4 hours I've been mapping out and defining the various colors and schools of magic, what they do and what uses they have. At first I thought "This is gonna be easy, I play Final Fantasy" Ugh. Because I wanted to be original and not just copy and paste from another work I used other fantasy worlds as influence on my own. And Cripes! Coming up with an entire hierarchy for magic isn't easy AT ALL. And after all that work the back of my head was pounding and I needed to lie down for second. While it was uncomfortable I feel a tad bit accomplished that I cared enough about my writing to create an entire system for just a plot element. If this was some time ago maybe I'd like to say a year ago I wouldn't have even bothered and probably woulda taken the magic schools out and just winged it in explaining it all. I myself am surprised at how much I've grown as a writer and how much writing has grown on me.
I built magic system that often caused me to reevaluate it because as I laid out scenarios on how it would work and how I wanted it to work I noticed how it was contradictory or it didn't match with what I planned. If I could find holes in the idea, then so would my readers. The more I crafted and built my world, saw how the world changed because it existed. I would have never been able to do that a few years ago or at least nowhere near as well.
Weird thing is I know what you mean. My world is starting to expand on its own. Recently a character who was originally planned to be a traitor has no reason to become one, but he's still a racist. The main antagonist is going to be around for roughly 3 times longer And some story arcs were melded together because they just make sense to