[Book Spoiler] Is Tywin being set up to ...

[Woman of War]

But the showmakers had altered the Tysha story in one important aspect at that episode from S1: as far as I remember Tyrion did not tell that he "went last" with Tysha - or am I wrong?

This is an understandable change since they have aged up all characters and Tyrion was, as far as I remember, sixteen in the series when he married Tysha. So he was not the child anymore that was sexually abused by his father who forced him into unwanted sexual activity of the most violent kind. Someone who has to bear his part of guilt but is a victim of sexual assault first of all. Tyrion, at sixteen, could have been expected to show more courage and standing against his father than thirteen year old little Tyrion. So making him "go last" with Tysha would have painted Tyrion far darker than in the books since a sixteen year old is no child anymore and would bear far more guilt for his part in the rape of Tysha.

This also would not contrast his behaviour with Tysha so clearly to not raping Sansa at his father's command, as Martin had intended in the books.

But if Tysha as important motivation should disappear from Tyrion's storyline we can as well stop all speculation that Tyrion will ever meet Tysha, be endangered by the presentation of a FakeTysha or anyone will find Tysha in order to annull whatever marriage since I do not think that D&D will alter the story's ending for the important protagonists that Martin has given to them. A character that disappears from the story can't have any implications on the final outcome.

[Mr Smith]

I'll be severely disappointed if Tywin were to kill Shae rather than Tyrion. That whole sequence where he goes into his father's bed chamber, kills Shae, then moves on to his father is probably the single most important sequence for Tyrion's development as a character. Its also possibly my favourite moment from ASoS, and it would be absolutely criminal to change it.

[Tywin's bastard]

If Tyrion doesn't kill Shae I'll probably stop watching the show, however grudgingly. Along with killing Tywin and his failed marriage to Tysha, it's probably one of his most important and life-changing decisions.

I don't think him killing Shae was that important. The lesson from that was already learned during the trial and him killing her was just the effect of that lesson, not a lesson itself. The lesson of that scene was all about Tywin as I see it, and Shae being there put Tywin and all his harsh words in a different light.

That said I do of course want Tyrion to kill Shae so things go as in the book. My only gripe is that they'll stick with the strangling, which wouldn't have killed Shae (you need to strangle someone for several minutes after they pass out in order to kill the person).

[Abaddon]

I hope you're right. It truly would be butchery to

remove the Tysha storyline from Tyron

They spent a LOT of time with the story of Tysha (with a minor edit) in S1. Why would they do that if they weren't going to follow it through to its conclusion? Doesn't make sense.

[Abaddon]

I don't think him killing Shae was that important. The lesson from that was already learned during the trial and him killing her was just the effect of that lesson, not a lesson itself. The lesson of that scene was all about Tywin as I see it, and Shae being there put Tywin and all his harsh words in a different light.

Tyrion killing Shae is terribly important. Killing his father is justifiable, Shae not so much. I think the "whitewashing" complaints about Tyrion are a little over-the-top but if he doesn't kill Shae I'll be right there with the rest of them howling about it.