Graham Nardone has recently confirmed on his twitter that there are new things in store for foundations in Island Paradise. He supplied the following picture and information:
Foundations still default to the same height, the terrain around them was raised.
You can raise terrain around them so only one stair step is necessary for sims to climb up on them (same height as platforms).
For more information on Island Paradise, please read our fact sheet, linked to at the bottom of this post!
Island Paradise Fact Sheet