Uru had/has so much potential. If we utilized everything, I wonder it's possible to make a kind of game-within-a-game.
Suppose a puzzle Age gets released. But suppose a puzzle solution requires the pattern on a certain type of plant or animal, let's say a lizard, native to that Age. The problem is, we only find lizard skeletons, and a journal states that this species is extinct. But maybe there's a Relto page in that Age that adds these lizards to your Relto, so you collect it then go back to your Relto and find the pattern.
Suppose a personal journal in that Age refers to a more detailed journal in Chiso that gives you details to solve a puzzle.
Suppose the writer/restorer of that Age left a clue that refers to a specific hood, and the imager or some unique documents in that hood contain clues to progress in that Age.
Suppose that Age would refer to a public garden Age that had previously been released innocuously that contains cave paintings or sculptures that help solve a puzzle in the main Age.
Maybe the Age was originally create during the reign of a specific D'ni king, and the history book in the Hall of Kings could contain a puzzle solution.
Maybe, if Ahra Pahts gets released for real in MOULa, one or multiple addresses can be referenced and contain their own puzzles.
Maybe, one or multiple custom marker quests could somehow be automatically sent to players at a point in that Age that take place in familiar Ages like Gira and Er'cana that contain clues to progress in the main Age.
Any of the puzzles/solutions could have been created by a D'ni citizen, a D'ni survivor, or a modern explorer.
EDIT: Also the style of the puzzles depends on whether they were made by D'ni or by modern explorers. A modern explorer's puzzle might be like the puzzle of Sharper's aquarium where you look at an invoice. If there's a marker quest, it could have been made by a D'ni worker of Er'cana if that's where the markers were. Only a modern explorer would have markers in a place like the Cleft where we were already given access by Yeesha. The whole game-within-a-game could contain a combination of both types of puzzles.
These are just some nutty idea I wanted to share, what do you think?