This was my first fan fest, however I have been to a number of gaming/anime/comic conventions and have also staffed and run similar events (on a shoestring budget though).
The biggest thing that struck me is how the event seemed to be "cheaping out" in certain areas. It's not like SQEX or the event is losing money (unless they are then...)
Anyway, my suggestions for improvements:
1. Place the merchandise area in a separate room. Have more stalls open. Have designated "cash only" & "debit/credit" only stalls. Perhaps open the merch area on day 0 for a limited period for people who arrive early (although most people arrived early), or allow online pre-orders and have people pick them on on day 0. Also merch should be slightly less expensive. Giving people tickets to come back at "xx:xx" time like on day 2 is a good idea as well to reduce congestion/rage.
2. Place the main stage in its own area. This allows people to actually concentrate on the stage events without being distracted by all the other noise of the other activities. Live stream the main stage events into all the other event rooms (like was done in the food room).
3. The food room: Not really advertised and was just "there". Should have more FF themed foods a la Eorzea Cafe (but might be hard to pull off if food is being provided by hotel catering.) At least have more food options to buy (less pricey would be good too.)
4. The activities should also be in their own room with better managed lines. Other people have suggested different/additional activities so I won't rehash that, but I will add that there should be a Cosplay area with themed sets/backdrops, and an scheduled autographs area for the dev team and other celebrities. Oh, and also a triple triad tournament? I mean if you're giving out the cards........
5. More Guests should be announced/available to create a better fan experience. We expect the devs to be there and the musical guests were a nice touch, but having more guests like voice actors and the art team or even celebrity cosplayers would add to the fan experience.
6. Someone mentioned earlier that having "player volunteers" rather than the temp staff "staff" the event would serve attendees better. However depending on how the event is incorporated there may be issues regarding paid workers vs volunteers etc...
7. More "I beat xxxxx" t-shirts, especially for the battle type events, and perhaps more prizes for winning other events as well. The Cactpot draw and Hildibrand activity was a nice touch though.
That's it for now, I did enjoy the event despite some of the hiccups but some improvements are needed so that fans in JP/EU can have a better experience in the next couple months and so that the NA folks can also have a better experience in 2 years time. :P