On one hand...I´d hope the writers to be more creative than this...on the other hand...it fits and its quite logical (pardon the pun)...it´s what I would do if I were Michael
Yes...and I kinda suspect that Amanda figured out what it was by the time she suddenly went all stone face at the end of the scene and said "I will find him"...
More than anything, I'm hoping that she punched him in the balls. The simplicity would be refreshing. More than likely, she shamed, embarrassed or discredited him.... something devastating to his ego, even though Vulcans aren't supposed to have an ego.
What did Burnham do to Spock? Micheal gave him a inappropriately weird kiss, like the one she gave Amanda.
She repeatedly beat him at the timeless Vulcan game "Connect 64" always saying "Here, Diagonally" just to drive it home. Saw his Final Fantasy "Lulu and Yuna" fan art on his drawing pad, and told Amanda. She wouldn't hook him up with her best friend T'Tina. She made Sybok think Spock was in pain. Spock wasn't in pain. She took up too much space on the bench seat in the back of the shuttle when they went on vacation. Every time Amanda or Sarek looked back she scooted back. Took up all the space on the bathroom shelves for makeup and girl stuff. Broke his lyre. Did not replace lyre. Had T'Biff pants him in gym. Put red kool aid in the sehlat's pet shampoo (yes, they've given up in the future, that's actually the flavor, red, and everyone knows it now, and will admit it in the 23rd century). Spock had to walk a pink Sehlat that day. Made him think despite the fact she'd stolen all his mother's natural affection that she'd somehow be there for him in the end, but when his greatest moment of need game she betrayed him.
Perhaps she told him that she was the reason why the other children beat him up? (and that he deserved it) She could have stated she egged them on and told them some secret he trusted her with.
The most logical (no pun intended) thing would be to somehow involve Sarek's sharing of a portion of his own Katra with Michael to revive her. Worded in the right way - and shown to Spock (was he too young to do a mind meld?) I can imagine that would be what would cut the deepest - poisoning his relationship with both Burnham and his father at the same time, but keeping his relationship with his Mother semi-intact. It would also help to explain why he disobeyed his father's wishes and went into Starfleet - he was already, by that time period, harboring tremendous rage and resentment towards Sarek.
I want to see that fan art now. Though Spock should have better taste and go for some Lightning Fang action. (It’s a very thin slice of taste above lulu yuna. Unless it’s x2 yuna.)