Not every blue deck will try to squeeze a Pilaf or two, but the card is extremely powerful, as two more cards in hand could be the decider of whether you live one more turn or not
You can be much more sinister though, combining Flying Men variants with extra turn spells to hoard all the extra draws for yourself
Also suppose that our hand is largely filled with powerful, expensive six-drops
In a Limited environment where everyone is playing morph creatures and the average size of most creatures is about a 2/2 anyway, having a creature that morphs into a 3/4 without paying any mana whenever you feel like it ends up being a huge blowout
It could be as low as 13 percent, but all things considered, over the long-haul, 15 percent seems about right
Whenever you cast a noncreature spell, Thancred Waters gains indestructible until end of turn