I initially thought as much for that level because the first screenshot of the jungle level looked like it had some sort of emphasis on vertical platforming via mini islands.
But the videos have since shown me that the "islands" can indeed be big enough to get lost and immersed in. There's sections in there that I could stop, look around and feel as if I'm in any other gaming jungle. As long as they continue to embellish the foliage and expand the island sizes, I can see myself looking past the floating island theme.
I think it works fine for this specific level, but I agree that I would like more grounded levels afterwards. I wouldn't want to be constantly reminded that I'm floating out in the middle of nowhere when the inevitable Halloween or snow level comes in.