By that, I mean the various interactions with objects in the dungeon that're based on your race/profession.
Alchemy/Rogue can delete 25% of first boss's HP.
Engineer can stun all the constructs.
Shaman/Scribe can provide 30% movement speed buff.
Prot Pala/DH can spot the Demon Spy
etcetc.
I really, really love these mechanics, imo they added so much more about Class Identity/Fantasy. I don't know if this will be carried forward to BfA dungeons, but I will be very disappointed if it doesn't.
My random ideas for BfA dungeon class/prof specific mechanics:
1. Freehold (Pirate Den) - Rogue/JC can bribe the guards, allowing us to skip some trash. Monk/Panda/Dwarf can do the same by proposing a drinking contest, with the PC outdrinking everyone else in the pub.
2. Atal'Dazar (Zandalar) - Trolls can invoke blessings of their Loa, granting us small buffs.
3. Tol Dagor (Prison) - Scribes can forge letter from warden, sending the guards away. Rogue/Blacksmith can pick lock for shortcut route.
4. Boralus (City Siege) - Warrior/Paladin can rally the disorganized guards so they fight among side us.
Do you want to see more of these mechanics? Obviously, it will be limited, so we won't be required to bring a certain class just to clear a dungeon. But these little stuffs are what make Court of Stars, IMO, the best dungeon in Legion.