If the existing assault weapons ban expires, I personally do not believe it will make one whit of difference one way or another.
That's right. It was always a political and aesthetic issue -- not a crime-control issue. And, of course, that's the point. As Jacob Sullum observed:
The "assault weapon" ban is important as a precedent precisely because its justification is so slight. It suggests that you don't need a good reason to limit Second Amendment rights. It also invites further infringements down the road, as supporters take the critics' arguments to heart and start arguing that the ban is not broad enough. After all, it covers only a very small percentage of the guns used in crimes.