Totally agree with you. The "Dreams of Alpha Lupi" give me that sort of vibe; Something I've previously read in Marathon (Gheritt White Terminals?). I've also read some Speculations about The Ishtar Collective, a group of Warlocks who apparently were doing research on the Vex, and "Simulated realities" are mentioned as if we were all running a sim created by the Vex themselves.
And about "Joyeuse", all I know is that, as I've mentioned before, during development, Bungie said there was a certain AI on Mars, called Charlemagne, that was guarded by the Cabal. This caught my attention, all things considered (UESC Marathon = Made out of one of Mars' Moons, has an AI called Durandal; Destiny has an AI on Mars called Charlemagne, who according to stories was given a sword called Durandal, forged from the same steel as Joyeuse and Curtana). This would be a great thing to have but having played through all the game I doubt that's going to happen, and they simply ended calling a Warmind "Rasputin" instead of Charlemagne. Who knows. I recall mentioning this on the reddit article I posted recently on here though.