The leopard change is an expression: bàobiàn, to go from rags to riches. A transformation which takes time and attention to detail. It is like the finely detailed pattern of the leopard's fur. It can change things for others as well, but hardly noticeable, especially in the beginning. After a while they will (maybe) realize that it is different than in the past.
The tiger change is spectacular, like the black-yellow stripes of the tiger, and like his magnificent appearance, which inspires awe. "Even before the augury truth is evident". Others have to agree with this transformation, because it will change things for them, and not in small ways.
"Small men shed the skin of the face"
Below at left modern and at right old bronze and oracle bone characters for 'shed face'. Often the ancient 'face' is already depicted as just an eye, like in the modern character.
''Shed' is the name of hexagram 49. It is removing something, dismiss, expel.
'Shed face' means to reform ostensibly/superficially. It is not a bad thing, just not very effective.
It might be possible that a Wu (shaman) could 'turn into a tiger/leopard' in order to convince people. Both for himself and for the people his message would carry more power, more connection with the spirits.