Maaseh Nissim on Pesach Haggadah, Magid, Dayenu 1:2
Rabbi Eliezer Ashkenazi, in his work Ma’asei Hashem offers another interpretation of Dayyenu.
He suggests that we should read the expression Dayyenu not as a demonstrative statement but as a question. “Would it really have been enough for us?” He uses a parable to explain this interpretation. Imagine a slave of a certain king who is rewarded with his own small kingdom. The slave, while grateful might say to the king: “How can I rule over my kingdom when I don’t have royal garb? How can I rule over my kingdom when I don’t have horses? How can I rule over my kingdom when I don’t have subjects and slaves? How can I rule over my kingdom when I am lacking in an understanding of the rules of kingship? With each request the king would give his slave what was necessary for him to rule over his kingdom. Similarly, we say to God, God you have taken us out of Egypt but is this really enough? You haven’t completed the job of making us a nation of priests and a holy people? It is only with all the miracles and gifts referred to in Dayyenu that God’s gift is complete.
Hope this is what you are searching for.