The BP that can create an unlimited amount of skins is a problem. People with land do want to get a T5 skin, especially higher tier lands, but not all can have it otherwise it is not rare. If they never get one, they are unhappy and if they get it and others do as well they are unhappy as it is not rare. When you limit the amount of skins a BP can produce you keep the skins rare and make players happy.
T4 evolution 1 = 30 skins
T4 evolution 2 = 25
T4 evolution 3 = 20
T5 evolution 1 = 15
T5 evolution 2 = 10
T5 evolution 3= 5
T3, T2 and T1 go up.
After creating the max, the BP is burned.
Still it will be hard as well to get the BP, but now more people have a chance to get one and others have the BP are not sour that more players have it as well. Do you hold to sell later or do you sell the skin now?