There were a few things that bugged me:
1) 90% of the cameramen forgot their tripods and had to do hand-held shots. Can be useful for dramatic affect during war scenes, but totally unnecessary for EVERY scene! I eventually got used to it, thank goodness, because those first couple of scenes just bugged the shit out of my eyes.
2) Gail - age 18. Don't cast a 22-year-old who looks like he's 27. I can forgive most characters who don't match their book descriptions to a tee, but for some reason, the look of this guy angered me - I felt like I was seeing that a-hole who never wears a shirt in Twilight. He had that look to him.
3) Relationship development. Where'd it go?
4) How Katniss got the Mockingjay pin / the district token - This only sort of bothered me; something I could have let go, but couldn't - Madge, the mayor's daughter gave her this token (all tributes are allowed one personal token in the games) and made a big deal about Katniss accepting it. But here in the film she finds it in a junk shop? And then it's like a big taboo to bring it with her into the Arena. I don't know. Maybe they're setting it up in a different way - like everyone else on the planet knows what it means except her (which is pretty true).
5) Avox and other sundries- they may have slipped in the word once, and alluded to them (mentioning getting their tongues cut out as punishment), but they were seen in just one minute, and were completely blurred into the background. They just CRAMMED information into the scenes, and mentioned things so fast, they probably just blew over the audience completely.
6) The missing confession that Katniss's affections were just for the cameras. Something they'll probably save for the beginning of the next film, but I wish it was in this one - maybe they didn't want to destroy the young lovey-doveys in the audience so they'd come back for more... whatever.
7) Cultural diversity. It didn't bug me too much at first, because that's what Hollywood does but every character is white except District 11, who are all black and farmers, yeah, no allegory there. Even the Capitol had a bright array of faces, from all nationalities.
EDIT: I REMEMBER WHAT ELSE BUGGED ME Career Tributes - the kids from Districts 1 and 2 train their whole lives for the Games. In the books, this is an illegal activity, but is overlooked. In the film, it's a special academy. No.
Things that didn't bother me so much:
1) Katniss's skin - Mediterranean or Italian, I thought, but hell, if one parent's so fair-skinned, she can still be standard white with an olive complexion. You wouldn't peg me for a quarter native american, would you? I'm motherfucking pale over here.
2) Omitting the dead tribute pickups / dog muttations - If you admit you won't be able to pull off something, say the muttations with the dead tribute eyes, then you don't need to set up for it.
3) Omitting the bum leg - this might show up in the next film, but I don't think the ailment will be bothered to go into the films.
4) The twirly fire dress during her interview - I felt like they threw that in there to play with the fire FX again, in case there's not going to be another movie. I'm just glad the dress didn't turn into a giant mockingjay, since its significance hasn't been revealed yet.
5) Rue and Cinna are black. When they described Rue, I didn't picture her black, I pictured her Native, or Indian, or maybe Hawaiian, but black... never crossed my mind. Her district's male tribute Thresh is exactly the way I pictured him, though. Cinna, I pictured as a small, frail, white older-middle-aged gay man with a subtle class about him. But I think Lenny Kravitz did it pretty well, too.
There are other things I wish were in the film, but I won't go too far into it.
I still liked Woody Harrelson as Haymitch, even though he's not really what I pictured. I hope when they make the video for the 50th Game, they'll be able to go back in time and grab a young Peter O'Toole (and dye his hair black), because that's who I pictured as young Haymitch.
Anyway, I'd better go before I remember the rest of what I was going to say about this film.