If you look at my profile I've already stated why I loved this convention (which was also my first). I share the same frustrations as everypony else, but this con remains the greatest two days of my life, as I'm a completely new person because of it. All of you who attended had something to do with it. Thanks.
The situation may have been worse than you thought. The drive from Virginia put me at the convention center on Saturday morning around 9:20 AM. Obviously the place was already packed by then. I waited in line for about an hour and a half before going inside to catch a panel (I wasn't about to miss the rest of the events just to buy vouchers). As you mentioned, heat and dehydration were a concern for security. Completely understandable and I support their decision to put safety first. The heat wasn't a problem for me because of where I'm from - I could have stood out there all day even if it was 20 degrees hotter and much more humid, and I have at some jobs I've held in the past - but I saw some New York and New Jersey folks looking ragged. My understanding is that their printer broke and that held up the line for an additional hour, so they may need to acquire some new, more reliable equipment for next year if they aren't going to do online voucher sales.
Sunday morning I got there at 4:00. Second in line for vouchers. Five hours later when the doors were about to be opened, a large crowd had amassed directly out front to go charging in. One of the staff guys came out and told those of us at the front that they weren't using that serpentine line for vouchers that day. They would be opening the doors and letting a line form however it did, with no real plan. The "autograph door" that was used Saturday remained locked. Being in front I muscled my way in the main doors with the rest of the crowd and got my vouchers within minutes, but the people who stood in that line outside for hours on Sunday did so for nothing. Maybe something changed later on and they got more organized, but when I walked by there a few times I saw the con store table mostly vacant and a massive line outside just hanging out, seemingly oblivious.
Please do this.