So I saw the movie again yesterday, and here are my revised thoughts regarding the ending:
I suppose one can make a case that they DID show Peeta's realization of Katniss's true feelings, although it is about as subtle as it can get. When they're on the train ride home, Peeta asks what they're supposed to do now and Katniss replies, "I don't know; just try to forget". She's back to "old" Katniss; stoic, very closed and focused on just surviving. You can see the hurt in Peeta's eyes as he registers what she's just said, and reasserts his feelings for her ("But I don't want to forget). But later when they're back in 12, Peeta watches Katniss as she finally lays eyes on her family and Gale, and again, he's clearly hurting.
Like I said, super subtle. But I guess now they can go into CF saying that they *did* plant the seeds of doubt in Peeta's mind. And I'm guessing that the "love triangle" will be heavily featured in the marketing campaign leading up to CF, so if we don't know about the tension between Peeta and Katniss now, we will before CF comes out.
One thing about HG making tons of money that makes me super happy is that CF and MJ are likely to have a dramatically increased budget compared to HG. Which is great, because they're going to need it. The horizons are greatly expanded in the next two books and 80mil isn't going to cut it. Especially in CF with all the different districts and an arena that just screams high tech and man-made...pretty sure all arena footage will have to be shot on a sound stage or some place very exotic. Not much in the way of jungles here. Maybe they'll pack up and film in Hawaii for awhile? :p
On another note, I'm re-reading the Hunger Games again, and I'm reminded of one of my small pet-peeves with the books, which is how incredibly self-aware Katniss is to the point of it being absurd. I know most of that is just a byproduct of the style of writing; Katniss is our ears and eyes so she HAS to make an observation on everything for the sake of the audience. But still, it is one thing about the books that I don't miss at all in the movie. Not having a running commentary in Katniss's head allows us to see her from a purely third-person perspective and judge her on OUR terms. And she comes off much more vulnerable and less...cocky? I dunno if it's the right word but anyway, I do like the movie's interpretation of her in this instance.