I love to imagine that Dedra Meero isn't actually any more competent than any of her lackeys, and that's she's tumbled upwards into her position because she's mastered the Imperial sneer of 'someone within eight feet of me just ripped the most rancid fart imaginable this side of the Force.'
That and her nearest competition for anyone smart enough to identify a light switch is Mirror Universe Bradward Boimler, which is. Y'know. The Imperial talent barrel's not so deep as it is more of a very shallow dish. Like Palpatine's gene pool, HIYOOOO~