DiArts
Here, a box containing all magic items creates another imbalance, as if it immediately diminishes the value of books, which are already rare and important!
Moreover, if a mage simply appears, and you have any specialist you want, all the magic items will be available, which is incredibly overpowered. In that case, it doesn't matter what troops or artifacts you have; it creates a terrible imbalance. Magic could be strengthened by adding a couple of shrines – one tier 3 and one tier 4 – and a couple of towers that provide +1 knowledge/power. Balance is achieved gradually, not by making such drastic changes!)
With the same logic, you could give warriors 10 archers right away and put an entire Haven faction into the artifacts – it's equivalent. In general, I'm in favor of careful balancing.
Well, it's generally a template about being overpowered, but I agree that no single branch should be an incredible imbalance. In the new editor, you can create a box with a random level 5 item; maybe that would work. I've updated the map.