NPCs are idiots. They don't know how to use the platforms. It would take a bit of reprogramming, and considering what happened between Koala and Giraffe updates, I'm not sure they have a programmer up to snuff to rewrite the code.
Or maybe it's one of those things where due to having more artists than programmers (a bad mix), they'd rather add content than fix or balance the content.
Thanks for the info.