The reason they're telling you about the steps they've taken to add an air of authenticity through collaboration with Polynesian artists is that the resulting work isn't going to feel as "Polynesian" to what guests might expect.
The "tiki" aesthetic of the original Polynesian Resort (and the Tiki room, etc.) isn't based on any real cultural influences. It's a romanticized amalgam of exotica that American G.I.s brought back after serving in the Pacific during WW2. I'm a big fan of tiki and the fan-made culture that's developed around it.
As Disney embraces a more truly multi-cultural perspective, they seem to be trying to incorporate actual cultural influences and moving away from artificial/synthetic ones developed through and for an American majority perspective. Because the Island Tower is being creatively developed with actual Hawaiian and Polynesian artists, it's not going to "feel" Post-War Tiki, it's going to be more (modernly) Hawaiian/Polynesian. I think they're hoping that by showing how it's authentic, they can address casual questions about why the whole thing doesn't feel more like Trader Sam's.
BTW, I see this dynamic happening across the Disney Parks. See: TBA, recent updates to the Jungle Cruise, some changes to the World Showcase Pavilions, etc.
