The architecture of the park has always been a bit in flux. It's never been completely "historic", although certain buildings were built in a historic fashion. When they were still building log cabin style buildings on park such as the current apple butter store, those were built in the same fashion as historic log buildings throughout Missouri. Some of the other buildings throughout the city were just kind of put up and themed and look cool, but they are hardly historic or even faux-historic, they are simply unique to that period of architecture at SDC.
I miss the cramped old buildings, the trees growing through things, and the litany of theme items tacked to walls and strewn around flower beds and such. I remember "old" SDC, and understand what some are missing.
On the other hand, consider the challenges of today: massive crowds, ADA requirements, fire suppression, A/C + energy efficiency, lighting & power needs, etc, etc. The "old" SDC was built by hand and was primarily a crafting village with a few oddities and minor attractions. Today we have a massive theme park with tons of technology and guest needs, in addition to the sheer number of guests. Way back then they hardly needed much electricity to even run the park!