The ground looks pretty soft to me... it looks to be that same rubber-type flooring/ground that was in the original Pooh's Playful Spot. You wouldn't believe the kids that I would see trip and fall in there and every single one of them would get right back up and keep on running (no tears to be found).
I don't see how the kids would hurt themselves that bad here either... even with the bouncy pads!?! But what do I know!?! :shrug:
From the video posted, it looks like the pads' bounciness has been decreased a LOT from the preview video with the Imagineer... Or perhaps it's just that for most kids, they don't weigh enough to push the pads down as far as the adult Imagineer.