Actually I actually thought it fit well with Varys character. Shae is not highborn. But he wants her out of the way. Tyrion can dispell the chaos that Varys is creating. Shae can help him do that. This might be what latter leads to her death. She should have taken the offer.
Richard III - Tyrion metaphors? Sansa? The Lannisters also killed both her father and brother as well, and forced her to marry Tyrion. Cersei's children are illegitimate. HOLY HANDGRENADES! a Tyrell.
At best: Brienne recaptures Jaime. Cat doesn't kill him, but he did agree to give back her daughters. This is where he broke his oath. So now he's prisoner again at best. Dead at worst.