Greetings,
please keep in mind that the Arcane Chamber of Sathkur (hard) is supposed to be a catch up instance, designed to reduce the grind for new or returning players to get back into the game over time. The instance is meant to supplement nostalgia content, not replace it.
Smaller parties will get significantly lower amounts of loot. While you can't take one of your own characters to boost your parties haul, it is highly recommended to try and fill the empty spaces with other players, as additional players aren't taking away any of your loot (except for cards, which are decently common).
We've not added RNG to the loot per se, we simply moved the RNG portion of what is gotten to a seperate step, instead of direct drops. While these drops aren't guaranteed, a player can expect to see at least one specialty material per 250 coins thrown into the well.
It is relatively rare that none of these materials are obtained, more commonly players will gain one or more materials.
Hooroo,
Brontes.