Sorry folks, I've been under the weather the last few days...
Pre-ordering is most important if you are going to stay there for two days. If you're just planning on staying there Saturday, then yeah, there isn't much incentive other than the fact that pre-ordering tickets allows us to improve this year's show rather than next year's show, Lord willing.
Personally, I'm always surprised when people say they can see the entire show in less than a day, but it all depends on what and how much you're there to see. I have heard - and agree - that Sunday has historically been the slower of the two days, but IMHO that's the best chance to really play some of the games. Sunday is also going to have an entire day's worth of speakers/panels this year which we haven't done in the past. I think Ben Heck will be on Sunday, I know Jack "Jersey Jack" Guarnieri will be there to talk about his pinball start up, and some other stuff has yet to be announced.
If this is your first show, then yeah, I can understand taking in one day, but there's a good chance you'll come back for two days the next time.
Later.