The following was my response on a thread on FB to someone with the same thoughts as you:
"... the article says that Disney is sending out surveys to see if people are interested in a "Star Wars section". If it's accurate, then that tells me it would be another "land". That would be much more feasible; they might find room for that. To create a whole new park, like they did for 'California Adventure', it takes a great deal more planning, real-estate and rearranging (and $$$).
Disney has already invested so much money, time, resources and thought into creating, expanding and refurbishing Disney California Adventure Park and the Downtown Disney District that there's really no more room on the property for anything more than simply a new "land". The logistics of it are staggering! The only way I could see them creating a whole new park is to buy out a large section of hotels and restaurants across Harbor Blvd. and build their own bridge across it, or do something similar with the neighborhood to the west across Walnut Street. (I wouldn't be too surprised if Disney pulled that off). They don't really have enough parking lot space left to turn into another park without also tearing down the Disneyland hotel and some of the Downtown Disney District.
Besides...if it's merely another land of Disneyland then it would be included in the price of admission!"
Check out maps.google.com and click on satellite...there's really no available land to create a whole new park.