I've never been to a con before, but I recognized how weird things were with the panels.
First of all, I understand that some time is needed between panels to set things up, but why have people crowd the walkway for an entire hour when the panel hall is completely empty?
Second, a complaint I heard a LOT of people saying was that the adult panels in the Chaos room are 21+ instead of just 18+. While I understand the need to card due to alcohol being involved, they had an excellent point that it's a fairly range of people to exclude, especially since carding for drinks can be done at the purchase of them.
Third, and this is more of a pet peeve, I personally don't like the question lineups. Mostly because I noticed that it's always the exact same people that manage to give their questions, the people that RUSH to the front as soon as the questions are announced. I honestly have no alternative solution, but it is a peeve that I quickly developed in the panels that required the question lines.