I don't mind the changes from the books, honestly, since they need to bring the everything to conclusion at the end of season 7.
But that's a problem the showrunners created themselves, having sped up Brienne's quest... In the books, Brienne's search for the Stark daughters only started in Book 4. Meanwhile, the show had Brienne search for them already in Season 4, which corresponded to the second half of Book 3. And now, in Season 5, Brienne might have nothing to do...
There's a similar, but even bigger, problem with Bran. Season 4 basically used up most of Bran's plot from Book 5. So... what are they going to do with this character? Are they going to drop this plot for a season or two?
I found Brienne's plot in FfC rather dull except for the end, so I really don't mind them changing things up.
Yes. It slipped from the actor that plays Hodor that he is not appearing in this season at all. And yes, Isaac is maturing very fast, but in my opinion he just makes up for the growth that was supposed to be in the books, but didn't happen and that Martin felt was too unrealistic for such young children.
I actually think they have used quite a lot of material from Dance with Dragons, they hit the end Bran's storyline, they are nearly at the end with Wall storyline, they are apparently dropping Aegon's storyline completely (established in trailer), they are very likely dropping Quentyn Martell's storyline (hasn't been cast) and they will most likely only skirt the Ironborn storyline as Victarion Greyjoy apparently hasn't been cast either. I think during this season we will see what remains to be made of the books.
Yes, we won't see Bran (or presumably Meera Reed, either). I doubt they'll recast Bran, though, unless the actor really doesn't want to return. He's well established at this point, so we'll see him again next year. I don't think we saw Lancel Lannister last season (I could be wrong—maybe he appears at the Purple Wedding or Tommen's coronation), but he's back now.
I agree, though it sounds like the show will largely take its own itinerary from that point on, using only some of the main material that will appear in WoW
. And the books now have so many characters, many of whom are now very far away from each other, so if they want to bring the show to closure at the end of season 7, they need to begin working towards that end now.