It seems she's working towards that, with the exception that she's going to use large parts of 3.5 as a starting point. Before you write that Designer's Bible, you want to have a mission statement.
I say it makes a ton of sense to decide what the end product should look like before you start designing and redesigning. She's starting with 3X as the background, which is her prerogative. So she's sketching out a way of thinking--does 15th level look like more like Conan (so you nerf casters hard so that they don't break the setting by existing--something like a hard ban on spells above 4th or 5th level, those spell slots used for metamagic or trade in for at-will spells) or more like Justice League (so martials look like the Hulk or the DC Captain Marvel)? Or option 3, which is harder for me write a quick analogy for, but you're probably starting with Tome of Battle / Path of War / Spheres of Might. (I don't know any of those 3 well enough to say any more.)
That's a decision that has to be made at the start.
EDIT: Oops.