Oh and I guess there's one more change
Once he has died once, you need to hit seven mana, in a deck without green, to replay him
The second ability gives very relevant protection, and its a wonder with mana dorks as it gives you an outlet for their mana and repays your Llanowar Elves by making it into a real creature
MTG has many mechanics that revolve around artifact numbers and density, so we have not only affinity cards here, but also improvise, metalcraft, and other artifact-matters mechanics and cards
In any case, the black Phyrexian Dominus is (unsurprisingly) a great card for aristocrats
The kicker is that when one of your creatures dies, opponents lose one life, and when an opponent's creature dies, you gain 1 life