I have three things that bugged me this year, although I feel bad for complaining because it's only my first year participating.
1. The prizes. It seems like the Cosplay Contest is the biggest competition at the con, yet we got the lamest prizes. I mean, for me I'm mostly proud of the bragging rights, but I spent a LOT of time and money on my costume, wig, makeup, etc and all I got was a plastic plaque and a pair of socks. And that was the best prize, too. Other gems included the second volumes of various unheard-of manga, wall scrolls (which were way too expensive for my "Kumoricash" anyways), and magazine inserts. This just seems ridiculous, especially because other contests and panels apparently had way better prizes, or so I heard.
2. The judging for the Best Novice Adult Group seemed... Unfair. The winners had costumes that (in my opinion) weren't as good as the Zelda group that was in the same category. The Makonas were also staff, I heard, which made it all make sense. I also heard that one of them was actually the Green Room Mom, which is absolutely ridiculous. I understand staff being able to enter, but staff who work directly for the contest should NOT be allowed to enter, and they should also not win over costumes that are far better than them.
That said, I wasn't at the judging so I have no clue what went into either of the costumes, but this really bugged me when I found out.
3. The music. This is a small issue, but my partner and I specifically told multiple people (including the sound guys) multiple times that our music needed to start while the MC was talking, and it ended up starting a few seconds after he walked offstage. Also, the couple that went before us didn't get their music at all, and they were in line before us to talk to the sound guys, so I know they had their music. It just seemed really unorganized.
Those were my three problems, but everything else went perfectly. The contest ate up a lot of the day, but that's to be expected, I suppose.