That means 1-5 cards of Rare or higher rarity, 3-6 Uncommon, 5-8 Common, and 1 Land card
A 6/6 for 6 mana is pretty standard, but it also gives you an immediate buff to one of your other creatures
So, we wanted to make sure that black had a way to deal a bunch of damage with a burn style spell
usually a 38-12 split 10 sources of "card advantage;" I use this term loosely, but mostly looking for card draw or any spell that nets me 2+ nonland cards in hand / directly into play 6 targeted removal split between creature / artifact / enchantment removal 3 board wipes 2 recursion 2 flexible tutors 1 graveyard hate 1 surprise "I Win" card That's always my starting point, which is then tweaked to suit the individual deck's strategy, and further tweaked with playtesting
This is here to cast your exiling stuff in your main phase
Given how powerful this card is on its own, however, I think this is more than a fair price to pay