Oh man, the Banished would have worked so well as the denizens of a shield world. I mean, we essentially have a series of Fallout Vaults, with the grand architect woken up and accessing them. The Shadow Didact could very easily have been working on his own logic plague, a counter to the logic plague that the Graveminds used to corrupt Offensive Bias and the other Forerunner AI – and then adapted that research to weaponize humanity's AI against them in kind. Or even Flood research that had progressed in the shelter of a shield world, mutated and cut off from the Gravemind's neural architecture.

The Halo rings were also research institutions after all, but compared to the Shadow Didact, the Master Builder was a destructive, shortsighted child. There could have been so many things hidden and locked away on the shield worlds, but noooo they had to go with a bunch of pirates lmao

Me and few buddies in my sci-fi writers group got together and drafted rough plans for a trilogy based on the Forerunner Saga lore, and we loved the idea of the sleeping giants of the Forerunners awakening, now that the galaxy had an all clear from a successful Halo ring firing. Like some kind of automated initialization after the detection systems reported that the Flood were gone, and the galaxy was ripe for rebuilding.