I believe you ' re right on both counts . 40 cards from 52 have log 52 ! 12 ! , 2 196 . 7 bits of entropy , and there are only 2160 different addresses , and so only effectively 2160 different groups of private keys that can spend from those addresses . I expect Ian will fix his bip 39 tool soon , based on how quickly he has reacted to previous issues I have raised . Edit note that 40 cards are taken into account only if you specify 52 cards if you only specify 40 cards then less than 40 will be used , and so on . This is a bug that will need fixing . <| sep |> I like the current system too , but I don ' t play at the highest levels . My suggestion would be to disable Legendaries in Mythic raids , at least for the first month or so . That would eliminate the need for the correct legendaries at the highest level of play , giving them a reasonably level playing field . And it would leave the system alone for the rest of us .