If Zoya is so stupid and useless, why was she chosen as one of the Darkling's main people?
Where?
Because in books, she was strong, yet ordinary Squaller. Perhaps promising, but hardly highly ranking, no matter what she likes to believe.
“You look amazing, Zoya! How are you?” gushed Marie. “We missed you so much!” squealed Nadia. “I missed you, too,” Zoya said. “It’s so good to be back at the Little Palace. You can’t imagine how busy the Darkling’s kept me. But I’m being rude. I don’t think I’ve met your friend.”
Shadow and Bone- Chapter 11
What stings, is that everyone knows it. It shows, when Zoya attacks Alina. If she were SOMEONE by herself, wouldn't at least one person note that?
to Ivan “... Please tell me you were there when he [the Darkling] told Zoya she’d be leaving Os Alta.” “I was.” “And?” I urge as we head down the hill to the birch grove. I’m a greedy thing, but how can I be expected to resist this gossip? Ivan shrugs, scowling. “He just made it clear that she’s replaceable and Starkov isn’t.”
The Tailor
Marie rolled her eyes. “She can’t bear the idea of anyone being the Darkling’s favorite.” I laughed and then winced at the stab of pain in my side. “I’m hardly his favorite.” “Of course you are. Zoya’s powerful, but she’s just another Squaller. You’re the Sun Summoner.”
Shadow and Bone- Chapter 11
She's rash, and to lead or bear considerable amount of responsibility, she'd need to unlearn that, start thinking about others and most importantly about impact of her (in)action. It might be why she was stationed near the Fold. I've theorised about it a few months back- it's the ideal position for her. She's (partly) answerable for the skiff and people on it, but danger comes in predictable form of volcra. It's the perfect place to learn what she's lacking.
She's barely out of school, she lacks experience- why would the Darkling give her important position, when he has hundreds of people to choose from? What's "main" about the person, who's driving a skiff?
Now where did the notion she's the Darkling's super special girl come from?
“Zoya Nazyalensky, who was one of the Darkling’s most favored soldiers.”
Yuri Vedenen; King of Scars- Chapter 9
That's an information coming from religious fanatic, several years after the Darkling's death AND merry application of current regime's propaganda.
Have you ever noticed how there's not a single mention of Ivan post-his death? We don't even know his surname. Aside from him, there's not one (1) named Grisha from his side.
It's easy to be remembered as the favourite, when you erase existence of anyone else.
Even in her memories, she's among the promising ones, yet not favoured, not hand-picked.
“... I was the youngest of the group and so proud to be chosen to go. I was half in love with him already. I lived for the rare moments he appeared at the school.” She shook her head. “I was the best, and I wanted him to see that … The older Grisha were all in contention for the amplifier. It was up to them to track the tigers and see who would earn the right to the kill. ...”
King of Scars- Chapter 27
The interest is one-sided, Zoya draws the Darkling's attention by stealing three amplifiers from other Grisha, her recklessness and short-sightedness, not her capability.
The closest we get to some sort of recognition, is in Aleksander's chapter in RoW, when he points out her deficiencies and admits some of it made her work hard.
And if Zoya ever learned to harness the power she’d been given? She was still vulnerable, still malleable. Her anger made her easy to control. When this war was done and the casualties counted, she might once more be in need of a shepherd. She had been one of his best students and soldiers, her envy and her rage driving her to train and fight harder than any of her peers. And then she’d turned on him.
Rule of Wolves- Chapter 26
I have one (rather big) objection- Zoya has never been a good soldier. She failed twice on rather important occasions- the amplifier and Alina incidents-, proving her self-control is lacking. That rage he's for some reason praising here, makes her dangerous to those peers she's trying to outdo.
But hey- he barely crawled back from the dead, his mental skills won't be at their best- why would he plan to manipulate Zoya without a single mention of Juris? The Saint isn't gonna disappear any time soon (if ever), and he's hardly Aleksander's fan.