I expect Invasion of Gobakhan to be a Standard staple in white aggro decks like Soldiers, Humans, and Knights and that it should have a chance to break into formats like Pioneer and Modern as well, both of which have tier white-weenie decks
The eminence-powered cost reduction helps you get onto the board a turn earlier, and since your 99 is so powerful, Ive seen an Ur-Dragon deck eliminate opponents never bothering to cast it
Which minotaur is your favorite
In playtesting, I found I had a hard time getting face-down creatures to the board reliably often
When you cast Pair o' Dice Lost, you roll two six-sided dice, returning cards from your graveyard back to your hand as long as the total mana value of all the cards you picked is less than or equal to your dice roll
That works for creatures, but noncreature spells dont make sense that way