Like most Magic: The Gathering cards, the value of Kazuul, Tyrant of the Cliffs depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Commander 2016)
The exclusive art will likely do a lot of heavy lifting in this regard, as will the cards innate scarcity as a promo
The trick to this type of design is to create some kind of connection between the two abilities so the aesthetics work out
Magda, Brazen Outlaw is a wonderful addition to dwarf decks, and it makes for an excellent mono-red commander
Imposter Mech is a fun take on a Clone
But I dont feel bad about Phyrexian Arena