Actually, I think he is much closer to Commodus: the "real" Commodus, not the caricatures in either The Fall of the Roman Empire or the more recent Gladiator.
He even, IIRC, replaced Nero's bust at the Colosseum with his own--and he was left-handed, which is a coincidence but also something in common.
Keep going, I'd like to see your reasoning.
That Hillary - who could also play several of their roles in The Decline and Fall of the Roman Empire - is supposedly a woman also fits the vain, self-absorbed Nero while its society and ecomonic base fell around her and barbarians began to sweep in across the borders (where invited in!) through a newly-defenseless Roman military.