According to the Gemarah in Shabbos 21:a (Rashi) the celebration of Chanukah was decreed because the oil, which was supposed to last one day, lasted for eight days. But at the same time the Jews were saved from the total destruction of their spiritual values and the loss of their Torah in a very miraculous manner. Wasn't this a greater miracle?

Let's ask another question: Our Rabbis tell us that Josef also experienced a miracle as he was being brought down to Egypt by the Yishmalim. They were carrying spices instead of carrying tar, so the that Josef would have a sweet smell as he travelled. Josef was being brought as a slave to an inescapable place of impurity and decadence, did the spices really help him? Could they change his frame of mind at such a time of desperation?

The answer to the second question is yes! From these spices Josef saw that G-d was still with him and he wasn't forgotten. These spices were a ray of light in the darkness and a revelation to Josef that it was G-d himself who was taking him to Egypt.

To answer the first question we need to understand that the purpose of a miracle is to reveal G-d's involvement ("the light of his face")in a given situation. It does not matter what the size of the miracle is, the main thing is that we see that G-d is with us. We know that a father loves his child not so much because he provides for his simple and basic needs but rather by the extra and special things which he gives his children. Surely the smaller miracle of Chanukah was that we were able to continue the mitzvah of lighting the menorah, but because it was smaller it revealed Hashem's love for us in a greater way. It was this small light of the menorah which announced to the world Hashem's burning love for his chosen people.

Based on Sichot Mussar