Genesis 25:27 says that Jacob was a perfect man. Your translations likely say “mild,” “plain,” or “civil,” but the term is tam. Kohler and Baumgartner say that this word means “in general… to be complete, perfect.” It seems that the reasons for translating it mild, plain, or civil, is to contrast against Esau’s description of being a hunter and field-man and a general disbelief that Jacob could be described as perfect or upright. Tam is the same word used of Job, though, and so it seems that the natural and consistent thing to do is to interpret accordingly. Jacob is an upright man. He is shrewd, to be sure, but this is a good quality.
We are told that Isaac loves Esau because of his belly (vs. 28), a character trait that Esau will share with his father. The man who loves to fill his belly makes unwise decisions, and it is Esau who is judged negatively for despising his birthright (vs. 34). Isaac is blind and fails to reserve enough blessing to go around. He tries to give everything to the wrong son. Esau marries all the wrong women. These two are of a piece.
Jacob and Rebekah will team up to use their craftiness to protect the covenant blessings. Rebekah sends Jacob off to her family, and when he marries his cousin, we’ve got a new Isaac, who was himself a new Abraham. His two wives proceed to play out the Sarah and Hagar rivalry all over again, and we will see that Jacob’s children wrestle with one another just as he wrestled with his brother.