Why would an omniscient being regret something? God, being omniscient, must have known from the start that man would disobey him in the Garden of Eden and afterwards. Nothing can surprise an omniscient being. Clearly, knowing that man wouldn't obey him, God decided to go right ahead and create him anyway. God could hardly complain that the outcome of his creation wasn't something he wanted and planned for in advance. But maybe you will argue that the creation of humankind was one of those times when God chose not to be omniscient, for a while, because God can do that kind of thing, so you say. If so, then it seems like the perfect God chose a terrible time to turn off His omniscience. Wouldn't you agree?