In this timeline Tokyo Disneyland would have opened up a few years prior, and that kept the formula of a traditional Magic Kingdom so to speak...so for Disneyland Madrid I would probably keep it somewhat familiar, Maybe reorganize the layouts from other Magic Kingdoms, but lands in the style of Main Street, Adventureland, Frontierland, Tomorrowland, Fantasyland, and some sort of Toontown or other sublands would be a good start...then theoretically in this timeline the 2nd park would open 10-20 years down the line, and step more outside the box in terms of theme.
Hmmm I would agree to an element of formula basics. I would pull from European culture a bit. But that’s also difficultly to this.. we (as in America) is a romance culture based on Europe so it’s hard to make something uniquely Spain than it is to making something China or japan infused.
So maybe the answer is to flip the castle park themes from the European perspective?
Maybe a Medieval European Main Street...An American romanticized "Fantasyland" of sorts. An early European countryside, or a Australian Colony similar to the "settlers" of Frontierland. Instead of a African/Polynesia/Caribbean dominated Adventureland, we focus on South America and Asia. Tomorrowland could change up a bit as well - not a Discoveryland though, something different.
I'm not saying go with these themes, but I do think it'd be cool to start looking outside the box of what a American Disney park is, while keeping similar styles lands via landscape and perception. Keep it similar to what the bare bones of a castle park are to guests, and make it European.