While Moses and others were said in the OT to have seen God, NT writers in John 1:18 and 6:46, and in I Tim. 6:15-16 take the position of Exodus 33:20 that no mortal has ever seen God, or at least not see Him and live.
For those who did see God, he may have reduced the intensity of his glory, or they looked at him through some kind of filter or diffuser. Consider that people could not look at Moses due to the radiance he picked up from being in God's presence. If we consider Moses to be like phosphorescent material after exposure to light, and the intensity of the light from the source had been reduced, how bright that original source would have been. The ancient people might say Moses saw God through some kind of veil.
Jesus, on the other hand, because he was holy and righteous, could have beheld the full glory of the Father without being evaporated. He had unique knowledge of the Father, but the Synoptic Gospels don't indicate when, or how, it was revealed to him. Since John writes about Jesus as the pre-incarnate Word, the implication is that at least much of the knowledge was already in him from birth. We are told that Jesus frequently went off by himself to pray, but we are never given insight as to what the Father replied or by what means he did (verbally, non-verbally, by angel, by vision, or just intuitively by the Holy Spirit).
Keep in mind that Moses, the prophets, or any other mortal only knew as much about God as He revealed to them. The full revelation was never given to any mortal (the original "need-to-know" directive). Consequently, these people occasionally questioned and even argued with God about what He would do, or how, or why He was going to it. With Jesus, it was clear from the beginning of his ministry that he had unique knowledge of the Father. Somehow, Jesus knew the Father's nature and will far beyond what Abraham, Moses, David, Daniel, or anyone else had. Consequently, he was able to speak authoritatively, not as teachers or even prophets did. The way Moses and the others saw the Father would be like one of us having to use filters to look directly at the sun. The filters enable us to look without strain or danger, but we miss details. As Paul wrote of knowledge of the coming kingdom, "Now we see but a poor reflection; then we shall see face to face" (I Cor. 13:12, NIV)--the difference between partial, restricted knowledge, and full disclosure.
While Matt. 11:25-27 and the parallel passage in Luke 10:21-22 speak of revelation, I think they also do speak of authority. In Matt. 11, Jesus transitions from his "woes" to cities where he was not well-received to praise to the Father for hiding truth from the wise and learned and revealing it to children ( the humble, trusting, and obedient--those not high up on the socioeconomic ladder who lord it over those beneath them). The Jewish leaders and teachers, many of whom did not accept Jesus as sent by God, considered God as their Father because they understood the Scriptures and kept the law (as evidenced by high socioeconomic status--a reward from God), unlike the common folk (whose struggles were evidence of their shortcomings before God). Verses 25-27 and Luke 10:21-22 seem to tie in well with John 6:44-46. To bring glory to the Son, the Father set up the requirement that the only way to truly know him is through the Son; only the Father fully knows the Son; the Father will bring people to the Son; and the Son reveals the Father to them as only he can do. When v. 27 states, "no one knows the Father except the Son and those to whom the Son chooses to reveal him," that says to me that the Son had the authority to make the choice of who would truly know the Father. We see this kind of thing happening when Jesus explains the parables to his disciples, but leaves the others wondering. In this sense, the Father has already turned the kingdom over to the Son, and the Son fulfills his responsibility in accordance with his Father's will.