My problems were more of the hotel than Otakon so those will be in that topic.
Size of the con. My god how nice it was not to bump into people all the time
Dealers Room had some really good vendors this year. I spent way more than I normally do thanks to the vendors.
Artist Alley, again, thanks to the size it felt like we had many more this year.
I got into the panels with no problems and rooms never seemed to be all full up.
Maps. While I was happy to see full size maps everywhere. It took me longer than I should have as they had no "You are Here" notes on them
Rain. Not really Otakon's fault but the Friday night I got wet trying to get food then later on I got sick (also due to the lack of sleep)
Lines. The main problem is that I could never seem to find any organization of the lines for the panels. It seemed to be all over the place or people would randomly line up. Due to the size of everything I didn't miss anything but man we need them better organized.
The bag check. I'm sorry but everything about that was a full waste of time and joke that caused the most problems for me. I know it seemed to be required by the DCCC but half the time they just "shook" the bag and didn't open it. Due to that it opened my pills in my bag and they were all in the bottom of my bag. When they did open the bag they seemed to be looking for a cartoon bomb than a real bomb. If they used any type of stuff I've seen the Mythbusters used they wouldn't be able to find anything. Heck, I've seen Disney World put more work into bag check than they did.