Pesach is the foundational holiday of the Jewish people, and the Exodus is the defining moment of Jewish history. A group of slaves formed a nation that, a mere seven weeks, later stood at Sinai so they could become a nation of priests and a holy nation. Mitzvah after mitzvah is observed zecher lyetziat mitzraim, to remember the Exodus. And these mitzvoth are in addition to the stand-alone mitzvah to remember the Exodus.
Often it takes our enemies to whip us into shape. “Rav Abba the son of Kahana said: Greater was the removal of the ring [of Achashverosh] than the 48 prophets and 7 prophetesses who prophesied for Israel, for all of them did not return them to good, yet the removal of the ring returned them to good” (Megillah 14a).