Tried her again with the TSK card pool. She's still bad.
The problem is her weakness.
Let's compare Minh to the first seeker in the game everyone has access to: Daisy.
Stats (Winner: Daisy) Daisy has a 5 int, whereas Minh has 4. Daisy has a lower Will, but a higher sanity and can safely fail will checks easier.
Survivability (Winner: Tie) Minh is more durable with 7 health, whereas Daisy is quite squishy with only 5. Minh has access to survivor cards like leather coat and Jessica Hyde, but Daisy has deny existence. Overall, they can both stay on the board pretty well.
Card pool (Winner: Tie) Some really good survivor cards came into play with TSK. However, they both aren't really going to want to delve too deep into their offclass as the seeker cards themselves are still pretty nuts.
Weakness and Sig Asset: (Winner: Daisy, by light years)
Daisy and Minh both get assets that completely lock up a hand slot,and limit each character to one hand. Daisy's signature asset completely locks down her weakness though, and basically ends up netting her one hand at the cost of increasing the auto fails in the bag by 1. Minh's weakness on the other hand completely locks down Minh's signature asset to where she basically can't use it if King in Yellow is on the field. For Minh to clear the King, she's going to want to be draw heavy so she can over commit. Since she's draw heavy though, she's going to be drawing the King a lot too. If youre playing with more than one actove hand slot, you always have the threat of King bumping one of your slots. Compare that to a draw heavy Daisy. Once she has necronomicon safely tucked in her book bag, it's a non issue for the remainder of the game.
Investigator ability (Winner: Daisy, by light years).
Minh can boost each investigator by one each time. They're probably not attempting checks they couldn't innately pass anyway, and this ends up essentially being pretty useless. Daisy on the other hand gets a free action on tome abilities, which she will most likely use on Old Book Of Lore. Draw (and even free asset play) each turn, pretty much every turn, guaranteed.
The librarian will outperform the secretary in almost every scenario. Since they're both competing for the same role... I find it hard to ever really recommend Minh. I have yet to find a deck build for her that Daisy can't do better, and as such she's a C Tier investigator for me.