Why did יעקב want עשו’s birthright? Is it because – יעקב wanted עשו’s blessing from יצחק, and he had to be the oldest in-order to receive the blessing? If so, how did יעקב know that as soon as his father gets old enough (in process of dying) he will then want to bless עשו. How did יעקב know way in advance about this discussion between יצחק and עשו, and prepared such an idea of lentil stew to get permission to take עשו’s birthright; way before יצחק was even in the dying process to promise a blessing to עשו in the first place? A little lost…. Alternatively maybe יעקב saw the future or something – that’s probably how he was aware about the blessing that will be given to עשו….What value did the birthright have towards יעקב that he craved to own it rather then עשו should?
The reason that Yaakov wanted the birthright was because at that time in history the one who had the birthright was the one who served as the kohen, bringing the offerings and serving H-shem. Yaakov felt that it was improper that עשו, who was a rasha, therefore he wanted to acquire it for himself, as he felt more suited for the job, and because he wanted to serve H-shem on a higher level. (See Rashi 25-31 from Midrash Rabba). He did not do it in order to get the blessings, (although it is possible that he would have wanted them). Even 49 years later, when Rivka, (Bereishis 23 6-13) his mother told him to sneak into his father and get the blessings, Yaakov refused, and it was only after she managed to convince him, did he enter the room to get the brachos, than were now rightfully his.