And while it's just our opinions here so you're certainly not wrong to prefer a different look, I really think what they showed is vastly superior looking to those mockups. I really don't see them deviating from what they showed too much. It's a sleeker, curvier version of the current Wii that is attractive and compact. I don't see why they won't stick with it or would even be showing off a complete placeholder for the exterior design of their console.
Sure beats a console that looks like it was made out of Lego's (Just teasing, but there are areas of that mockup with the square lines, complete lack of curves, and that extremely thick USB/SD slot door that gives it that feeling).