A bold move, given that the Emperor's memories of mindbulleting his shitty uncle as justice for him murdering his father in ancient Anatolia from Master of Mankind is one of my favorite lore bits.

Besides, if the Emperor isn't the ancient being everything thinks he is then you miss out on all of his former Perpetual friends calling him a tyrannical fuckwit and then fucking off to go be farmers on the edges of space to try and avoid the blowback of his failures.