Actually, Sylvians and Amazoness are easy games to Archfiends, I seldom lose to them. But yes, without Heiress, the consitency of this deck isn't the best, although a good hand can be unstopable
Spellbooks are likely useless against Invader of Darkness and Chaos Hunter. Even if they use Treacherous Trap Hole and Empress is on the field, it will also be useless as well.
Actually Archfiend decks are always vulnerable to some common meta decks, depending on the version, since you can only deal with some decks through tech cards. I would say it is tier 2. KoG worthy, at least.