Great John the Baptist

We had an interesting Bible Study tonight led by RJ, roughly based on Luke 1, focusing on the role of John the Baptist. A notable verse is Matthew 11:11:

Verily I say unto you, Among them that are born of women there hath not risen a greater than John the Baptist: notwithstanding he that is least in the kingdom of heaven is greater than he.

Previously, Jesus says that he's not only a prophet, but more than a prophet.
So why is John the Baptist so great?
He was a prophet, one of God's spokesmen.
He was MORE than a prophet; he's the one who prepared the way for Messiah Himself.
He was the last and ultimate prophet of the Old Testament theological era.
Of all the prophets, he is the only one who not only foretold Messiah's coming, but was able to physically point Him out. 
So how can he that is least in the kingdom be greater than one who is so great?
John knew not the cross nor resurrection; the humblest Sunday School student can describe both.
He anticipated the gospel; we participate.
The Old Testament, of which he was theologically a part, was only ever temporary; the era of the gospel will never pass away nor be superseded.