The treehouses were built in the 1970s and when they were rebuilt, they were required to have the same ‘footprint’. That included being raised up; from what I understand, that requirement was because the land they are built on is protected land.
All the videos I’ve seen of the Copper Creek villas show a ‘ straight in entry.’ They were built in 2016-2017 and were subject to ADA accessibility guidelines for access.
There are 26 separate cabins and the South Wing of the original WL resort building was also converted into villas. The original building was built in 1994, so would have been under the ADA and would have been subject to additional ADA requirements because of the conversion.
We stayed at WL long before the Copper Creek villas and found it very accessible for my wheelchair using daughter