This amazing affair, the great celebrations and grandeur with which this mitzvah was accomplished, is evidence of the exalted nature of this mitzvah. On other occasions when people would come up to the Beis Hamikdash, for example on עלייה לרגל or to bring up their מעשר שני, these mitzvos were not performed with this degree of grandiosity. This is indicative of the importance of this mitzvah, which was performed as an act of הכרת הטוב.
The Alshich Hakodosh says that because the middah of hakaras hatov is so crucial, therefore this mitzvah was so beautified. He quotes the Midrash (בראשית רבה א ד) which says that the mitzvah of Bikurim is one of the chief purposes of creation! The Alshich explains that this indicates that not only is this mitzvah the purpose of creation, but the basis for Bikkurim is הכרת הטוב to Hashem, and that is indeed the ultimate purpose of creation.
Lest You Forget
It is human nature for a person to get accustomed to that which he has, and forget Who has granted it to him. Therefore, we were given this mitzvah, to remind us on a yearly basis, where all our blessings come from.
The Alshich sees a reference to this in the possuk; והיה כי תבוא אל הארץ when you will come to the Land, וירשת and you will begin to feel like it is an inheritance that is inherently yours, and therefore you will not be grateful for it, and you will forget אשר ה' אלקיך נתן לך that it is Hashem your G-d who has given it to you, וישבת בה you will settle in there and become accustomed to its bounty. You will be so habituated, you will forget how blessed you are, and how grateful you must be. Therefore, you should bring Bikkurim, which will remind you that this land and all the blessings that you have, have been bestowed upon you by your Loving Father to Whom you must be eternally grateful.