Just got back from Nagoya. I personally think the fair is a bit over rated. Young people will not find it interesting at all.
The pavillions are educational to small children e.g. showing you what animals are endangered, what happens if the moon didn't exist, etc. etc. But for young adults, we were expecting hi-tech robots, new technology etc. and there was not much. No wonder visitors were mostly seniors and children in elementary school. For instance, there was this pavillion showing how magnetic-generated (I forgot what it was called officially) train works. This 3D theatre imitate what it feels like to be on such a train. This was no surprise at all since there already was a real one operating in Shanghai and some other places in Europe already.
And the lineups!!! I had to spend 4 hours to queue for this Hitachi pavillion which only took me 15 mins to finish. They only gave us a VR thing to put on our head and we were able to see wild animals and fishes. Again no surprise at all. If you don't lineup, there was practically nothing else to see. The shortest lines would cost you at least 1 hour, and they turned out to be boring shows with birds and flowers showing on a set of plasma panels (e.g. Moutain of Dreams Pavillion). So the a bit more interesting ones would require at least 2.5 hours for lineups e.g. Toshiba Pavillion, Power Pavillion, Spain Pavillion, etc.. And the countries pavillions were mainly shops selling ethical souvenirs e.g. China, Saudi Arabia, Nepal, etc..
And the fair was huge! There was no circular transport that could let you ride from one destination to another. There were these trams and bicycles but we had to lineup for them and then get off at the next stop, if we wanted to go farther we had to lineup again at the 2nd stop in order to go to the 3rd stop. Each stop costs us 200-300yen per person, so we had to spend over 1000 yen just to get from south of park to the north front gate (there were 2 stops). Of course you could walk, but it was so hot and so crowded you just wanted to get into some where with air-conditioning as soon as possible.
And the shops are full of queues too. There were queues for getting into the souvenir shops, and queues for the cashiers. And that most popular Toyota Pavillion (robots dancing show), there was practically NO WAY of getting tickets unless you go there (by cars not public transport) line up at the front gate at 6:00 in the morning (OR, you could also buy a ticket and book online 1 month ahead of time). We took the 1st train to the expo site at 7:00 and by the time we arrived at front gate at 8:30 there were already many people (gates open at 8:45). By the time we got in at 9:15, Toyota tickets were already all gone!
Of course there was this good side of the show, It was beautifully constructed and the IMTS cars were amazing! Infrastructure was very organized and washrooms were so clean! Expo staff were very helpful too. There were many restaurants to choose from and price were reasonable. The pavillions looked very nice and the entire site was like a big theme park. I particularly loved the green expo icons - "forest grandpa" and "forest grand child".