D.C.A. is the ideal location for conceptual artwork related to the creation of Disneyland; I would be very happy if The Disney Gallery, for example, was moved, in some form, to the new park.
Similarly, many of the exhibits in The Walt Disney Story, featuring "Great Moments with Mr. Lincoln" would be best in the new park. For example, the animation pavillion may be able to house the re-creations of Walt Disney's offices. I think that since Disney has dismantled its Feature Animation department, the pavillion needs to expand its scope to include the full breadth of productions that have come from The Walt Disney Studios.
At D.C.A., I would like to see more of Walt Disney's career in California explored. There are several historical buildings that could be moved to the new park. For example, the original garage in which Walt Disney made his first films deserves a place of honor in the Hollywood section to parallel Mickey's movie barn/movie garage outside his bungalow in Mickey's Toontown.
A remaining structure from the Hyperion Avenue studios was moved to the Burbank lot when it was built, so I think that building has the potential to be moved again to the new park and, perhaps, be paired with the replica of the "Mickey Mouse & Silly Symphonies" sign that was also at the Hyperion plant.
The existing, outdoor Muppet*Vision queue would be better replaced with a shop or restaurant, and, on the opposite side of the street, the meaningless window displays on the exterior of the animation pavillion would be better exchanged with a replica of the "Disney Bros. Studios" storefront.
The Dominguez residence, the only structure that is original to the property on which Disneyland now resides, should be moved from its current location, backstage, to the citrus groves of Bountiful Valley. That house has an interesting history that may lend further authenticity to D.C.A.