It DOES NOT MATTER how many wins a person has. Generally the morphing being done will be to counter your CURRENT OPPONENT and since you have no idea who you are facing next, for all you know, you will be the one who is destroyed the next round because you come up against someone that has morphed their deck into a great counter against yours unbeknown to them. Someone with 4 wins can just as easily lose to someone with 4 wins as they could against someone with 0 wins. Without the foresight of knowing EXACTLY who your next opponent is, you don't know what deck you will be playing against, and therefore it does not matter in the slightest how many wins or losses a person currently has.
So in conclusion, it doesn't matter which way pairings happen, as long as they happen.
