it sounds amazing!!! i think they should also have more branded shops etc. like hershey's that came with rct3 expansion for example pizza hut, mcdonalds. Also in most theme parks you don't get random burger/kebab stalls (well mabey small ones) you get great big walk-in restaurants, they should these in game aswell.
Also i like what rollercoastermatt said about real parks, i seem to remember that with the expansion for rct1 (or was it 2?) it had parks with it like alton towers.
EDIT: Last thing: queues. You should be able to get fastrack queues, another entrance at the back of the park, possibly a queue for front row seats and being able to stop the ride without the queue closing.
Also i like what rollercoastermatt said about real parks, i seem to remember that with the expansion for rct1 (or was it 2?) it had parks with it like alton towers.
EDIT: Last thing: queues. You should be able to get fastrack queues, another entrance at the back of the park, possibly a queue for front row seats and being able to stop the ride without the queue closing.