(You expend 4 as you spend your fourth total mana to cast spells during a turn.) Whenever you expend 8, exile the top two cards of your library
Now we have scry lands (Temples), cycling fetchable duals and other utility lands for days and you rarely see these used
Well, if you can get it onto Elenda, the Dusk Rose, or Elias il-Kor, Sadistic Pilgrim, you might have a good time
There are some very relevant cards which dodge IoK like Yawgmoth, Thran Physician, Goblin Charbelcher, Omnath, Locus of Creation, Primeval Titan or any of the new Elementals, but just looking at the list of most played cards in Modern shows how many other cards Inquisition of Kozilek hits