hm... double the risk of howling mine, giving your opponent 2 cards first, plus the higher casting cost makes it that much harder to protect, so, in most cases, it will draw them 2 cards and pull an artifact removal. And no tapping tricks to abuse it.
I can't even begin to imagine what getting a free 8/8 trampler would involve.
Perhaps some new keyword like: Firstborn 1 (when - enters the battlefield promise your firstborn child to WotC)
Of course, there would also be Firstborn 2 and 3, maybe even Firstborn X (X cannot be zero...coffee doesn't fetch itself you know).
Thanks for filling another hole in the spoiler, as well as clearing the details of other cards in the other threads. The current state leaves us with these:
4 Aven Trailblazer (Creature - Bird Soldier?) Common
26 Ethersworn Adjudicator (Creature – Human?) Mythic
38 View from Above (Instant) Uncommon
46 Grixis Slavedriver (Creature – Zombie Giant) Uncommon
47 Infectious Horror (Creature - Horror) Common
56 Wretched Banquet (Sorcery) Common
60 Canyon Minotaur (Creature - Minotaur) Common
81 Ember Weaver (Creature - Spider?) Common
97 Wild Leotau (Creature - Cat) Common
122 O Rhox Bodyguard (Creature - Rhino Soldier) Common
125 O Skyward Eye Prophets (Creature - Human Monk?) Uncommon
127 O Sphinx Summoner (Creature - Human Wizard?) Rare
129 O Vagrant Plowbeasts (Creature - Beast) Uncommon
AFAIK, the Slavedriver was hinted by Zesty before he bid us farewell, the other have no hints.
As for the Font, well, your opp gets to draw 2 cards first, and there's no chance to shut it down by tapping. Maybe with Master Transmuter, or the Kederekt Parasite...
CaptainBlack posted in the speculation forum on the "what is the :1mana::symw::symb: cost for" thread that Ethersworn Adjudicator has the abilities :1mana::symw::symb:, :symtap:: Mortify (destroy target creature or enchantment) and :2mana::symu:: Untap ~. He couldn't confirm the P/T though. Cost might be :3mana::symu:.