I think the characterization might seem "erratic" because the player is not privy to a lot of information about the characters beforehand (for example, 2B's true nature), which informs their actions. Though that said, Yoko Taro (the game's director) also does love to explore the extremities of the human condition- his Drakengard series (of which Nier is a spinoff) is even more extreme in its characterization and dark in its content matter than Nier. I definitely do think that there are aspects of Nier: Automata that are better appreciated by playing it (especially the ending), and the gameplay itself is quite slick (especially when compared to the original Nier or Drakengard), though it does suffer from balancing issues later on in the game after you've completed many of the sidequests and upgraded weapons.