I've seen "MSR" (Modern Sporting Rifle) used in print advertising now from major retailers. I'd say that's about as much of a re-definition as we could ask for.
Obviously the Assault Rifle moniker is incorrect, but I don't know any gun folks who use it to describe their AK and AR clones anyway. And I think it will be, well forever really, before the media stops using "Assault Rifle" or "Assault Weapon," regardless of what WE choose to call it, so I doubt there's going to be a sea change of public perception on the matter.
Or rather, there already HAS been a sea change. When I was growing up (not really all that long ago) ARs and AKs were seen by a whole lot of the shooting public, and ALL of the non-shooting public, as military rifles (literally only good for killing people, as I was told by a close family member), and anyone who owned them was either fringe-ish or an immature kid playing army.
Now that has changed COMPLETELY (from 10% acceptance and use among gun folks to 90%, at least) and across much of American society. When the largest general goods retailer in the US ... or world! ... sells them at their little sporting goods counter in most of their locations (AFTER the dark days of the no-guns-at-K-Mart '90s, no less!), it is probably time to admit that what folks are calling them doesn't much matter anymore. At this point we could probably start calling them "baby-killers" and it wouldn't much damage their level of acceptance in society!
Heck, we've already co-opted "Evil Black Rifle" as a mark of pride rather than derision.