While I don't think it was every said in the books, my interpretation was she's basically setting him up as King of Meereen, legitimised on her rules and her terms, so she can finally go to Westeros (leaving him behind as her 'Satrap'). Perhaps even one step further Baristan's death reminded her of her true mission…

Euron Greyjoy, for all his chapters,still hasn't done anything particularly relevant. I have a theory they're avoiding the 'too many characters' problem, by pushing him over to next season which will finally bring her to Westeros.

Very possible (might let Varys off the hook ;-) ). Plus the three eyed crow said to Bran he would fly. But the whole 'dragon has three heads' usually reads as three Targarayens.

I think all this set up of GreyScale and the stonemen we're going to get Tyrion's not catching greyscale moment soon which I think is an important set up to that reveal (particularly if we get Dany's visit to the Plague - with the "Targs can't catch disease' line. The Dragon has three heads and Jon, Dany and Tyrion…

In the Books it's a big thing that Tyrion takes a dip in the GreyScale water but doesn't get infected. And then later Danny visiting the plague victims because Targs also have super-immune systems. All this premonition about GreyScale and the publicity shots of the river boat which must be the next section of the…

Marriage consumation -> In the Book it's announced the Margery isn't still a Virgin, so we're left with the possibility that Cerise's self-destructive moves against Margaery will still manage to bring her down. OF course we now can't have that big announcement!

I wonder if next season-book we will see Littlefinger take down the Freys?

In the Books it's a major thing that various North Lords join Stannis to 'save [false] Arya'. So Sansa does have an Army, not in the Vale, but in the North.

I think a lot will depend on whether they end with things unresolved like the book, or by ending with Stannis arriving at Winterfell which Martin seems to open WoW with. TVwise if the Boltons are going down, better do it at the end of season 5 than the start of season 6