I am the perfect person to ask that to, bc I live about 40 minutes away for DLR, and I just came back from WDW.
Magic Kingdom WDW Is MUCH larger. The castle in DLR is so small, although it looks better. The point of WDW was to use ALL of the swampland Walt Disney bought, and to turn it into a tourist attraction. He bought ALOT of land, so everything is big. However, in CA land costs much more, and at the time, that was what Walt could afford, and he built it. People dont want to rebuild a new castle, bc that castle is our only connection to him...