I think this is an awesome idea, and I'd love to see it fleshed out and brought to life. It's the Narrative Team's goal to make Splinterlands more than just an autobattler. Eventually, we hope to make it much, much more immersive, and your concept is one way we could do that.
Currently, ranked battles are fought in the arena, and they would tell the story of your fortune and fame. As you mentioned, Conflicts are another dimension of your character. Meanwhile, we are driving for new game modes where you are the hero of the story.... like you said, all recorded on the blockchain, so the possibilities are infinite. Boss monsters, missions for different splinters, different arenas to fight in, etc. that will all be chapters in your hero's journey.
I am definitely excited for what's to come!
RE: Expanding the Splinterlands Universe: Integrating Player Lore into Ranked Battles and Land Economy