Some key scenes take place there, but if you tally up all the locations featured in the film there are many, many locations. Its not true that 90% of the film takes place there, that's ridiculous.
I didn't say 90% of the film. I said 90% of the Gotham scenes, as in the outdoor scenes in the city.
- Opening tree lighting scene in Gotham Plaza
- First Red Triangle attack in Gotham plaza
- Mayor baby snatch in Gotham plaza
- Batman/Penguin/Catwoman meeting in Gotham Plaza
- Batman/Catwoman rooftop fight is overlooking Gotham plaza
- Bruce and Selina meeting in the street in Gotham plaza
- Mayor's speech and the 2nd tree lighting ceremony in Gotham Plaza
- Ice Princess dressing room tent where Penguin abducts her is in Gotham Plaza
- Ice Princess held hostage in building over looking Gotham Plaza (which she falls down into later)
- 2nd Penguin and Catwoman meeting where he tries to kill her is on a roof overlooking Gotham Plaza (they're both looking down at the citizens there going crazy because of the bats attack)
- Penguin's speech which Batman sabotages in Gotham plaza
- Rocket toting penguins converge into Gotham plaza
And if you want to get technical Schreck's department store is in Gotham plaza so all the scenes there are based in it like Catwoman breaking in and blowing it up, Schreck and Bruce meeting, Catwoman's origin etc.
The majority of the outdoor Gotham scenes happened there. The city felt dramatically reduced and smaller. Smallest version of Gotham in the movies easily.
Perhaps it doesn't reflect reality, but it certainly reflects perception.
It's both reality and perception because it's a reality.