It seems like everyone I see on PVP has their heroes traited out pretty thoroughly. I haven’t found a way that feels even remotely reliable to get the arcane level trait stones. I do explore on the highest difficulty settings, and that doesn’t seem to improve my chances of getting anything better than a major or runic (if I am lucky) stone. I literally have only ever gotten arcane from the better chests (gem, and event if I recall). It feels like it would be a practical impossibility to get 10 arcane of a specific type because I would probably have to do about 500 explores in a kingdom, or spend thousands of gems because gem chests aren’t predictable for what arcane stone you might get.
Am I missing something for a way to get the higher level trait stones with any degree of reliability?