The Funpark is very much designed for active kids play, lots of things to climb on etc. For an adult one day is plenty to see the park area. There aren't any mechanical rides like a carnival, just things to do and a lot of water play. Staff all seem to speak English fine.
Nuremberg should have a great Christmas Market, the area is known for toys and Christmas decorations. I spent 5 days in Nuremberg and didn't quite see everything. There are two toy museums, the main one and then one that's part of the Germanisches Nationalmuseum. Neither has Playmobil, but lots of great toy animals and dollhouse stuff. You can go up in the tower of the castle for a great view.
My photo set of the Funpark, shop and factory pictures is at
http://www.flickr.com/photos/71879015@N00/sets/72157627780021984/, and my Germany set which includes the Funpark etc photos plus Nuremberg, the Germanisches toy museum and the Tierpark is at
http://www.flickr.com/photos/71879015@N00/sets/72157626716096693/