A powerful physical metaphor is intimated by the story of [Yaakov's] wrestling [with the unknown man who was no man at the end of this week's parsha] Jacob, whose name can be construed as "he who acts crookedly" is bent, permanently lamed, by his nameless adversary is order to be made straight before his reuinion with Esav.Jacob's whole life is entangled in moral ambiguities. His father's blessing and whatever wealth he acquired in Haran came to him through deviousness. In almost all of his dealings, he is the bargainer, trader, wrestler and heel-grabber. The Sages say "tofasta merubah lo tofasta." he who grabs gets nothing, and in some ways this is the story of Yaakov's life: He grabbed for the blessing, but after many years have passed Esav is a sort of prince with a retinue of 400 men and great wealth, while Yaakov has only his bondmen and his flocks.
On the eve of his meeting with his more succesful brother, Yaakov has a strange encounter, and it leaves him damaged. I think Alter is right when he says the mysterious stranger is the externilization of all the Yaakov has to wrestle with in himself, a doubling of all with whom Yaakov has to contend, and of all of his experiences to date. The mark of his experiences --of tending the flocks of Lavan, and of raising 11 children after travling to Haran with nothing but his stick-- has been left on Yaakov, but as is often the case, struggles have made him a better, stronger man. As Alter notes, the text strongly suggests that his experiences, represented by the wrestling match, have cured Yaakov of his crookedness and made him ready to face his brother. In fact, when day breaks he is no longer Yaakov (crooked) but Yisrael (lordly).
Later, the point is driven home when the brothers meet and, instead of lethal grappling, Esav embraces his rehabilitated brother with affection.