This feels similar to not finding a game fun once I understand the underly system that generates it. The magic is lessened (even if applying simple rules can generate complex outcomes, it feels determined)
But every turn becomes a tight little puzzle to solve, with surprisingly many possible outcomes. Often, situations that I thought were hopeless, do have a favorable outcome after all, I just had to think further than I usually did.
it is very different, but also has the feeling of triumph for each puzzle
In Minecraft, I personally want to progress in a "natural" (within the confines of the game) way, and build fun things I like. I don't want to speedrun to a diamond armor or whatever.
In Crusader Kings, I actually try to take decisions based on what the character's traits tell me, plus a little bit of own characterization I make up in my head.