According to this news story, and comments made at the recent Disney investor's meeting, there have been more than one million visitors to the theme park since it opened on June 16th. Even if that number was exactly one million and it took around six weeks to reach it that implies the park could see over 8 million guests this year.
The large park is capable of holding some serious crowds during the day, and the story also notes that visitors are staying longer than officials had hoped - and the stated hotel occupancy of 95% is a good sign indeed. To keep the momentum going the park is already working on expansion; a new land based off of Toy Story is rumored to be in the works with an accelerated opening.
Depending on how the guest flow continues, Disney is also happy that they have plenty of land for more hotels and attractions, should they be warranted. Personally, I think the trip would be worth it just for Pirates of the Caribbean: Battle for the Sunken Treasure!