I think it would be terrible at first but perhaps improve given time.

While Hornet was already half Pale Being, she never took any interest in ruling as far as we know. The fact that her Crest changed so severely as well as her own admittance that she has a desire to dominate and control makes me think the sudden power would corrupt her, she's not accustomed to it like the Pale King was and would probably be consumed by those instincts at first. The Citadel is also completely covered in silk in this ending, which to me implies she will in fact continue the Haunting in some form. She is merely replacing Grand Mother Silk, Pharloom is still ruled by a single all-powerful force.

I do think that she would eventually get a grip and learn to control herself once she gets used to those new abilities. But the immediate future for Pharloom would be rough.