"Tze'akah Gedolah" would have told us the extent of Esav's cry. What are the implications of the additional words, "... u'Marah Ad Me'od"?
Oznayim la'Torah (to 27:41): Esav had spent a lifetime of grooming his father for the Berachos - bribing him with the venison that he hunted, by putting on a show at being a Shomer Torah u'Mitzvos 1 and by honoring him to the extreme. 2 And now, at the last moment, Yaakov with his Chochmah (and with the help of his astute mother) had pulled the rug from under his feet.
What were the ramifications of Esav's bitter cry?
Midrash Rabah: Because Yaakov caused Esav to cry out, the Pasuk in Esther informs us that Mordechai "cried a loud and bitter cry" (Esther 4:1). And as for Yaakov himself, for having caused Esav to weep, he was made to weep when he met Rachel for the first time. 1
Why did Esav say "Barcheni Gam Ani Avi"? He should have said 'Osi'!
Ha'amek Davar: Esav understood "Gam Baruch Yihyeh" to mean, 'because also he is my son.' If so, you can bless also me, for also I am your son, and call you Avi!