The idea is thrilling, but for casting
worldslayer you need 5 mana and another 5 for equipping, since you have no mana acceleration that means that the combo can start to go off by turn 6. Modern is a format where by turn three you have lost against many deck, a turn 3 karn, liberated, affinity, humans, storm, dredge, they all are so quick and consistent. Have you tried going to an FNM with this list? Really like the concept anyway, but i think you need a way to speed up thing, or slow down the opponent, since you have a black mana you should pack some disruption IMO