My vote is because even if a generation has something really good (Sableye, Mismagius, Chandelures line, Aegislashs line, Marowak/Decidueye/Oricorio/Mimikyu/Lunala, Zoroark/Dragapult/Spectrier, Ceruledge, Annihilape, Flutter Mane, Gholdengos line), its offset by a bunch of lame stuff as well. Gengars line is perfect and theyre ALL high tier.