Yaakov addressed his request to be buried in Israel and not in Egypt directly to Yosef. It seems that Yaakov thought the matter required legal confirmation because he made Yosef swear that he would do as Yaakov told him. The proof to this is that Yaakov made Yosef swear. Ramban בראשית מז:לא() as well as other commentators say that Yaakov never suspected that Yosef would not follow Yaakov's word, but that he wanted to make the request stronger so when Paroh heard of it he would not decline the request. If Yosef had taken an oath, then Paroh would have to allow Yaakov to be buried in Israel. Rashiנ':ו'( ) says that the only reason Paroh allowed Yaakov to be buried in Israel was because of the oath. Paroh would have wanted a prophet and outstanding personality like Yaakov to be buried in Egypt but because of the oath made by Yosef, he had no choice but to allow Yaakov to be buried in Israel.
From the outset, Yosef realized that there might be problems with Paroh (see Ramban to מה:א and Rashi to מז:ב). That is why, according to Abarbanel and Sforno, that Yosef tried to avoid taking an oath because he did not want to have to go back on his swear if Paroh did not want to violate his oath. However, Yaakov wanted a commitment from Yosef and the only way to get it was to make him take an oath.
When Yosef went to Paroh to make the request, he changed his father's words so that Paroh would agree. Yaakov wanted not only to be buried in Israel, but not even to be buried in Egypt until the time came to go to Israel. Yosef diplomatically only told Paroh of the burial in Israel and not of the fact that Yaakov would not even be buried temporarily in Egypt.
We see that Yaakov and Yosef realized that they had to be excruciatingly careful in their relationship with Paroh. They realized that even a small misstep could prove to be disastrous. The great genius of yaakov and Yosef where needed to properly deal with Paroh. It is not surprising, accordingly, that out trouble in Egypt began after Yosef's death (see Rashi to מז:כח). Similarly, after Yosef's death, the enslavement began. The Torah שמות א:ח() relates "ויקם מלך חדש המצרים אשר לא ידע את יוסף". In light of the above, this pasuk can be understood as saying that since Yosef was not alive to deal wisely with the new king, this left בני ישראל vulnerable and without protection. We pray to Hashem that He protect us from contemporary Parohs and provide us with great leaders like Yaakov and Yosef, who can deal with such potentially harmful people.