What did the fact that Esav was born ruddy signify?
Rashi: It was a sign that he would be a murderer. 1
Da'as Zekenim, Hadar Zekenim: It shows that his blood was not absorbed, so Yitzchak decided that it is dangerous to circumcise him. When it persisted for a year or two, Yitzchak decided to wait until he is 13; but then Esav did not consent. "Dam Saneisa v'Dam Yirdefecha" (Yechezkel 35:6) alludes to this.
Malbim: It hints to anger, envy and all bad Midos that come from the redness. He absorbed the filth, cloudiness, physicality and Dam Nidah, so Yaakov came out clear.
Gur Aryeh: His complexion was a reflection of his future character. Otherwise, why would the Torah record this?
Why did everybody call him 'Esav'?
Seforno: Refer to 25:24:1:2.
Hadar Zekenim: The Gematriya of Esav is the same as Shalom. If not for this, no one could stand up against him.
Riva: Regarding Esav it says "they called," for all saw him. It says 'va'Yikra' (singular) about Yaakov's name, for only women present at the time of birth saw him holding the ankle.
Oznayim la'Torah: Everyone called him 'Esav,' because, due to his abnormal appearance, he stood out and was talk of the town, whereas Yaakov, who was a normal looking baby, did not attract attention, and it was only his father who called him 'Yaakov.'
Malbim: His bad natures were already finished at birth. Everyone called him so, for all understand matters of physicality.
Targum Yonasan: Including a beard, as well as teeth. Malbim - hair is a sign of [an improper] excess of the brain, and improper intellect. He could not accept proper attitudes, Midos and true beliefs that depend on intellect, or act justly in matters that depend on the body.
Ha'amek Davar: Body hair is a sign of adulthood. He was already Asuy (finished). Oznayim la'Torah - they called him Esav and not Edom - until he declared, " ... min ha'Adom ha'Adom ha'Zeh" (25:30), because, bearing in mind that his face too was covered with hair, his ruddiness was less prominent than his hairiness.
Why was Esav born hairy, while Yaakov was smooth?
Maharal (Ohr Chadash, p. 186): Of the two of them, Esav took any aspect that was negative and deficient, and so he emerged physically repulsive. Yaakov was left physically (and spiritually) clean. 1
QUESTIONS ON RASHI
Rashi writes: "It is an indication that he would be a murderer." What does this mean?
Maharal (Derech Chayim 5:9, p. 247): Esav was the diametric opposite of Yaakov, in that Esav was a murderer, while Yaakov did not even see Keri in his life. 1 Similarly, Chazal say, "Yaakov Avinu did not die" (Ta'anis 5b).
Maharal: (See Rashi to 49:3.) Seed is the root of life, and wasting it is akin to murder (Nidah 13a).
Rashi writes: "'Entirely like a cloak of hair' - He was full of hair, like a woolen cloak that is full of hair." What is Rashi adding?
Gur Aryeh: He was not like a cloak made of hair, which is smooth. Rather, he was entirely like a cloak of wool, which is full of (protruding) hair.