According to the Gemarah in Shabbos 21:a (Rashi) the celebration of Chanukah was degreed because the oil, that was suppose to last one day, lasted eight. But at this same time the Jews were saved from the total destruction of their spiritual values and the lose of their Torah in a very miraculous manner. Wasn't this a greater miracle on which to degree the celebration of Chanukah for all future generations?
Lets ask another question. Our Rabbis tell us that Josef also received a miracle as he was being brought down to Egypt by the Yishmalim. They were hauling spices instead of hauling tar with them so the that Josef would have a sweet smell as he traveled. 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 in such a time of desperation?
The answer to the second question is yes! From these spices Josef saw that HaShem 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 HaShem 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 Hashem'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 Hashem is with us. The way we know a father's love for his child is not so much that he provides for his simple and basic needs but rather by the extra and special things which he rains upon 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 reveled 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.
This word is based on what Rav Chiam Shemuhlavtz said in his book Sichot Mussar