I can understand why Margaery doesn't drop Sansa immediately like she does in the books, but it really would've fit their theme for the episode as stated up top in the first post, if Margaery had like she did in the books.
An important thing to note is that the Yunkai treat Dany as though she's a Dothraki conqueror to be bought off, while Dany has instead adopted an ideology to hold her army together: Freedom.
Freedom's just another word, though for nothing left to lose.
Tyrion if he really wanted to be happy with Shae, would have let go of his desire for power and respect where he knows that no matter what he does for his family, he's going to be hated or attempted to be killed. You'd think he'd learn after one attempt too many to let go of the things that are poisoned gifts.
Despite the dress being supposed to not suit her, Gwendolyn Christie manages to make even what's supposed to be a ridiculous dress look somewhat respectable. I don't know how--but she does.