GM-Less?
Having recently read Goblin Quest (no GM) and Crush the Rebellion (taking turns being GM) amongst other rules I’ve read with these two concepts – Blades certainly would not require much tweaking to become a fully collaborative (as in equal agency) game. There’s certainly enough mechanics for balance, and if you include the heist deck and possibly with additional events, complications and whatnot to make life a bit random in a scheduled manner, it would not be hard to accomplish. It lacks an overall story arc – but so far from actual plays I’ve read, there hasn’t been much call for one in a campaign.
Even with a GM, it’s best not to go in with a story arc in mind, I think. Circumstances and coincidences and “the favorite parts” of sessions build up, and eventually take a shape and direction. As that happens, then new things coming in find their way into that growing shape and direction.
I think the key to playing with no GM who has overarching responsibility is to pass the GM role between scenes. There’s always someone to manage the interface of fiction and mechanics, but just for that scene, or that down-time cycle.
That pulls the pressure off for preparing for the GM, and also allows each player to play a character instead of having one set apart as GM.