I 100% support that Locke as love talker theory ruins Taryn's character and I think it ruins half of the plot actually because then Madoc is a shitty dad who allows his daughter to be charmed and abused, Jude fights with her sister over nothing since it's not her fault and Nicasia is not a cheater but basically a rape victim. Too many conflicts just fall apart.
Also I don't think it works technically. When Oak tries to love talk Wren he needs to talk to her directly to make her do what he wants. He's not giving an order directly but he still needs contact. And Taryn came up with a marriage blackmail before she came to see Locke if I remember correctly so he didn't have an opportunity to charm her.
Yeah, giving Locke that ability and having him actually use it makes no sense in the story we were given. Based on what happened with Oak and Wren, it's easy to tell when some is using love-talk on them. I could maybe buy Taryn might not be aware (I'd need a really good explanation, though), but Nicasia? Cardan? None of the various Folk that Locke was dealing with? None of them knew?
Oak accidentally used his ability on his friend from school, and it was obvious something was wrong. The ability is not subtle. If Holly Black makes it canon that Locke used it on her, I will ignore it. Forever.
This was too good of a point to leave in the comments. Oriana not only was willing to intervene to protect one of her foster daughters from actual royalty, she knew Liriope and about her power. She worried for Taryn's safety after Jude was exiled. If she really thought Locke was a real threat, she would have warned Taryn, just like she warned Jude about Dain. People under sell Oriana's care for the girls, but she didn't want to see them hurt, or Madoc's reputation damaged. If anyone would have stepped in with a warning about Locke, it would be her.















