Like many others here, I'm also 1) excitedly looking forward to the movie, 2) disappointed by the trailer, and 3) taken back by the casting choices. Peeta definitely does not match the description in the book right now, but maybe the movie magic can make the choice more convincing. I'm not surprised by Katniss being played by an older actress because almost ALL older teenage characters on TV and movies are played by actors/actresses well into their 20s: (almost) no one is convincing as teen-aged and hasn't been for a while.
In regards to the books, I actually really didn't like the whole love triangle thing...I didn't want much focus on the love part at all. And one can kinda see where the whole "Oh but he/they couldn't possibly like me" thing was going from a mile away. But I am awfully biased here because I'm not into romance movies OR books, and I find that in this case it takes away from the story that is so beautifully compelling and tragically haunting by itself. With that being said, I can definitely understand WHY there's a love story/triangle to it, given the intended audience of the books. So I bear with it, and even appreciate the male characters.
As much as I like happy endings, I also actually appreciate the somewhat anti-climatic, the somewhat unresolved/unsatisfying closure of the books because it seemed more realistic and much less Hollywood. None of that "happily ever after" against all odds no matter what crap. I'm so hypocritical haha...I like happy stories and happy endings, but I really rationally can't stand them sometimes.