Late dvar for Toldot #2:

In parshat Toldot, in the beginning of the story of Yaakov's obtaining of the bracha via subterfuge, we are told (Bereishit 27:1)

וַיְהִי כִּי-זָקֵן יִצְחָק, וַתִּכְהֶיןָ עֵינָיו מֵרְאֹת; וַיִּקְרָא אֶת-עֵשָׂו בְּנוֹ הַגָּדֹל, וַיֹּאמֶר אֵלָיו בְּנִי, וַיֹּאמֶר אֵלָיו, הִנֵּנִי.
"And it came to pass, that when Isaac was old, and his eyes were dim, so that he could not see, he called Esau his elder son, and said unto him: 'My son'; and he said unto him: 'Here am I.'"

We are told this upfront because this fact will play an important part in the story. That is, since his eyes are dim, Yitzchak will not be able to distinguish between Yaakov and Esav.

Rashi, based on a midrash Tanchuma, says that Yitzchak's eyes were dim as a result of the smoke from offerings to idols generated by "these" - those mentioned in the preceding psukim, Bereishit 26:34-35:

וַיְהִי עֵשָׂו, בֶּן-אַרְבָּעִים שָׁנָה, וַיִּקַּח אִשָּׁה אֶת-יְהוּדִית, בַּת-בְּאֵרִי הַחִתִּי--וְאֶת-בָּשְׂמַת, בַּת-אֵילֹן הַחִתִּי.
וַתִּהְיֶיןָ, מֹרַת רוּחַ, לְיִצְחָק, וּלְרִבְקָה.

"And when Esau was forty years old, he took to wife Judith the daughter of Beeri the Hittite, and Basemath the daughter of Elon the Hittite.

And they were a bitterness of spirit unto Isaac and to Rebekah."

The midrash connecting Yitzchak's blindness to Esav's wife's idolatry must at least partly based themselves on the juxtaposition of the psukim - Esav's taking wives and their aggravating Yitzchak and Rivka to Yitzchak's eyes becoming dim. I would have to see the midrash inside to see what else sparks it. Is it the word מֵרְאֹת, which sparks other explanations of Yitzchak's blindness (e.g. the angels crying at the akeida, cited also by Rashi), מֹרַת רוּחַ from the preceding pasuk (?with רוּחַ meaning wind?), or one of Esav's wives being names בָּשְׂמַת, or perhaps the similarity of וַתִּהְיֶיןָ in pasuk 26:35 with וַתִּכְהֶיןָ in 27:1? It should be interesting to check out.

At any rate, along the same line as this medrash, I found a great pasuk/psukim towards the end of the parsha, when Esav decides to take another, non-Canaanite wife:

Bereishit 28:6-9:
וַיַּרְא עֵשָׂו, כִּי-בֵרַךְ יִצְחָק אֶת-יַעֲקֹב, וְשִׁלַּח אֹתוֹ פַּדֶּנָה אֲרָם, לָקַחַת-לוֹ מִשָּׁם אִשָּׁה: בְּבָרְכוֹ אֹתוֹ--וַיְצַו עָלָיו לֵאמֹר, לֹא-תִקַּח אִשָּׁה מִבְּנוֹת כְּנָעַן.
וַיִּשְׁמַע יַעֲקֹב, אֶל-אָבִיו וְאֶל-אִמּוֹ; וַיֵּלֶךְ, פַּדֶּנָה אֲרָם.
וַיַּרְא עֵשָׂו, כִּי רָעוֹת בְּנוֹת כְּנָעַן, בְּעֵינֵי, יִצְחָק אָבִיו.
וַיֵּלֶךְ עֵשָׂו, אֶל-יִשְׁמָעֵאל; וַיִּקַּח אֶת-מָחֲלַת בַּת-יִשְׁמָעֵאל בֶּן-אַבְרָהָם אֲחוֹת נְבָיוֹת, עַל-נָשָׁיו--לוֹ לְאִשָּׁה.

"Now Esau saw that Isaac had blessed Jacob and sent him away to Paddan-aram, to take him a wife from thence; and that as he blessed him he gave him a charge, saying: 'Thou shalt not take a wife of the daughters of Canaan';

and that Jacob hearkened to his father and his mother, and was gone to Paddan-aram;

and Esau saw that the daughters of Canaan pleased not Isaac his father;

so Esau went unto Ishmael, and took unto the wives that he had Mahalath the daughter of Ishmael Abraham's son, the sister of Nebaioth, to be his wife."

Rashbam explains that Esav was trying to curry favor with Yitzchak in the hopes of getting a better blessing. I would object that it seems too late at this point, in which case it would be more of a late realization that Yitzchak did not approve of his wives. Is Esav a good son?

However, pasuk 8 states וַיַּרְא עֵשָׂו, כִּי רָעוֹת בְּנוֹת כְּנָעַן, בְּעֵינֵי, יִצְחָק אָבִיו - that is, taken hyper-literally, Esav saw (realized) that the daughters of Canaan were injurious to his father's eyes. Beforehand, this might not have mattered much, but here he had lost his bracha as a result of taking wives who worshipped idols and thus damaged his father's sight. Therefore, he took an additional wife, not of the benot Canaan.

Update: I guess you could say that he found her "easy on the eyes."