Like, for real I think that the ttrpg rules for Spire are kind of clumsy. It's easy to stack all the d10s you need by angling in the domain you need, and the real game to me is more about approaching it like a spy and not just hammering away at the incredibly powerful abilities the game gives the players.
The Mechanics get refined for Heart, but I still love the material of Spire; I just would prefer to engage with it mediated through some other kind of system. Which is why it would be great as a CRPG. My complaints on Fallout is that it dominates pacing by letting consequences delay while also increase in threat level which is really rough for a GM to deal with. Yet, if it was just experienced by a player it would be wonderful.
Furthermore, holy shit I can just imagine recruiting cell members as a Minister of our Hidden Mistress and trying to get moves made on a big mission on a level of Spire. Holy Shit. The crazy stuff that could be happen would be wild. I have to stop typing because I'm going to be so sad that it doesn't exist lmao. Read Spire: The City Must Fall.