No speculation intended, it was from an unreliable source, and so unconfirmed. =) Take it with a pinch of salt. If confirmed, it will not be in Nusajaya, and it will not be so soon.
It was mentioned in the press last January that Uncle Lim was doing a study on the feasibility of opening an outdoor theme park next to Johor Premium Outlet Store. Last year August, it was reported that he had conducted the study since 2009, and if there was a need, the attractions would be built in the second development stage of the JPO.
"Genting Bhd is planning to develop additional attractions such as a hotel and an international water theme park to complement its Johor Premium Outlets (JPO) here." quoted from sources.
http://biz.thestar.com.my/news/story.asp?file=/2010/8/6/business/6807292&sec=business
http://biz.thestar.com.my/news/story.asp?file=/2010/1/22/business/5521820&sec=business
Just these few days, there is unconfirmed source saying the planned theme park will be built, but no dates given. However, it is mentioned that the 800 rooms 5 stars hotel is expected to be ready by 2013. The Theme park will follow. However I think Chief Lim would want to wait and see, depending on how well Legoland will do. So we have to wait some time. If this is coming from Genting Berhad, I am more confident it will be world class and not end up like the fun fair at Danga Bay.
Another speculation is that the planned water theme park at Austin Heights is confimed. Banner spotted showing the planned water theme park.