Stats are hard to look at. It's common to see people comparing urban areas to rural areas and pick their stats to claim that a heavily regulated city has more crime. On the flip side it's quite easy to do the opposite. Without something universal in effect you aren't really going to accomplish anything on scale anyway. If you have tough regulations in one state and it's neighboring state has little, well you aren't going to fix much. Chicago has high gun violence and high regulation, it also borders states with far laxer gun regulation. So what gives?
I don't think an assault weapon ban is going to do a whole lot anyways. It's really sad what happened in these last few mass shootings but overall, the majority of gun related violence and deaths aren't committed with assault weapons to begin with. To really dent a problem like you're having you would need to do something about handguns, which isn't going to happen anytime soon. Is it logical to have some of these 'assault weapons'? Not to me, but like I said I don't think banning them is going to solve anything. In my mind a shot gun or your standard bolt/lever action rifle is all a sensible person would need for any practical purpose.
A major problem is how accessible they are and how unaccountable people are for these weapons. If you want these weapons I think you should be held very accountable for where they go and whose hands they end up in. This would might make people much more reluctant to turn around and make a profit off a weapon they know might turn up in bad hands (as it would be traced back to them as the original owner) and make people much more responsible for safekeeping of a weapon. Weapons get stolen and I totally get that but it would take quite sometime alone with the proper tools to get at the weapons we have at home.
We have handgun bans in Canada and our violent crime/deaths with firearms per capita is fairly low. Not as low as a place like Australia, but unfortunately they don't have neighbors accessible by land on the largest undefended border in the world with very relaxed gun laws as neighbors. It's pretty humorous how many ceased handguns committed in crimes here are traced back to the U.S. But hey, with a markup of 9-10x the base price of what an American smuggler would pay for a typical handgun in the U.S, the risk is often worth the reward