"The scenes of the past and the future were presented to the mind of Jesus. He beheld Lucifer as he was first cast out from the heavenly places. He looked forward to the scenes of His own agony, when before all the worlds the character of the deceiver would be unveiled." The Desire of Ages, p. 490. (Emphasis supplied)
From the time of Satan's rebellion in heaven, the problem was not so much a misunderstanding of God's character, as it was of Satan's character.
"Not until the death of Christ was the character of Satan clearly revealed to the angels or to the unfallen worlds. The archapostate had so clothed himself with deception that even holy beings had not understood his principles. They had not clearly seen the nature of his rebellion." The Desire of Ages, p. 758.
"Satan is a deceiver. When he sinned in heaven, even the loyal angels did not fully discern his character. This was why God did not at once destroy Satan. Had He done so, the holy angels would not have perceived the justice and love of God. A doubt of God's goodness would have been as evil seed that would yield the bitter fruit of sin and woe. Therefore the author of evil was spared, fully to develop his character. Through long ages God has borne the anguish of beholding the work of evil, He has given the infinite Gift of Calvary, rather than leave any to be deceived by the misrepresentations of the wicked one." Christ's Object Lessons, p. 72. (Emphasis supplied)
If God had acted differently, His own character would have been misunderstood. But rather than leaving any to be deceived, God gave His Son to die for us. It was not God's, but Satan's character that was not perceived by the angels. Nor is it discerned by those who follow him today.