im sure it is only made some class specific gear more easier to find outside duncraig while duncraig will have less biased on specific gear.
im personally favor any method that make each hours you spent in game should carry you forward toward your next item progression, directly or indirectly.
if you are playing solo without trading, chance are you will be finding a lot of "dead item" that dont carry you forward once you already reached 500 eaten signets.
d3 kinda solve this with more crafting recipe in kanai cube, poe have advanced crafting for rich people with super expensive orb (or there is even way to create item from scratch to powerful rare).
Median do have several method for progression, but there are a lot emphasize on getting lucky and spending more time.
Maybe we do need some higher crafting reagent above signet (like enchanting crystal) but at least IMO, it should be somewhere between early-mid endgame stuff (i already mentioned this in suggestion like many time before).
But again, I havent spent much time on current 1.1.3 patch so I have zero idea on what progression / hour you get from median, but usually I stopped playing once I felt the game is too grindy to be fun.