^ it's highly unlikely that the park will become as big as Europa Park because of its location. On one side of the park there are residents living so the park can't expand there. On another side there is the highway. On the third and last side there is a natural reserve. The park has been trying to get a permission to expand onto the natural reserve area (under strict conditions, e.g. buying compensation areas) for more than 10 years now.
Residents living close to the park, environmentalist, a garden club and some politicians have dragged the process on forever. At the moment it looks kinda positive, but when and if at all a expansion is happening is still unclear. The park has always had these problems (noise, height restrictions, space) and while it sometimes feels frustrating, I share the sentiment with others that these problems are what nurtured the creativity, which made the park so unique.
But even if an expansion is happening, I would keep my expectations in check. The last public plans of Phantasialand spoke of an Aquapark and a concert hall on the new land as well as removing administration building from the park area. Yet these plans are now again quite old and the plans before that looked totally different. So nobody knows what will happen.
For the next years it will most likely be replacement of old attractions (Temple of the Night Hawk / Hollywood Tour, Geisterrikscha)
Speaking of the new construction area mentioned above: Depending on how much administration/maintenance they move the area can get a lot bigger than Klugheim. Although this has been mentioned before, I again want to to point to an interview
with the Lead Designer of Phantasialand. He mentions there that the new area will be bigger/more expensive than Klugheim.
Last but not least a PSA
On the 28th of October there is "Tag der Brühler" where everyone living in Brühl or going to school in Brühl can visit the park for free. Yes you read that right: Everyone! Not only will the park rammed, but also every moron who doesn't give a f*** can enter. You have been warned.