It's funny you mention that, because just about everything that has been changed in the game so far has been done so via our requests. I have only seen a small handful of truly original ideas that yoshi's team has thought of on their own without our input.
So yes, we make most of the game for them and the other 15% of it comes from their own creativity or is borrowed from the likes of FFXI and other previous FF titles.
It's kind of nice to know that we control this games destiny in a way, but at the same time that can be a scary thought.