Let me say this again, because I cannot stress it enough. The AR-15 as sold to civilians is normally chambered in the same round as most hunting rifles and is, in fact, used primarily as a hunting weapon. Ease of use, decent scope mounts, and polymer or steel bodies can reduce wear, reduce weight, reduce recoil, reduce missed shots or misplaced ones(so the animal doesn't suffer -- also, some of those are exclusive).
It can be said, since many hunting rifles operate in the exact same way, that a hunting rifle is overkill for self-defense, too. There'sa reason why it's so popular -- and yes, it could be because of how it looks.
Similarly, the AK-47 variants that civilians may own (until recently, IIRC), are limited to semi-automatic, a gas impingement rechamber, but it's less common in hunting, cheaper overall.
The reason that the AR-15 is so popular, and in that caliber, is because of surplus brass from the military's 5.56×45mm NATO cartridges. The weight of the completed round is different, as is the power, but most hunting is varmint hunting regardless -- not deer, but coyotes, wolves, boar, and things smaller than that.
So! The ammunition is cheap because the military doesn't reuse its old brass, making the AR-15 platform a simple choice for an effective hunting rifle. Action indistinguishable from most varmint rifles chambered in .223, stopping power indistinguishable, the only real difference is accuracy beyond 300m...well, at which point the round is a lot less effective, too.
What I'm saying is that the AR-15 is a suitable hunting rifle for most applications, and is in no way overkill if the quintessential hunting rifle isn't. It just looks scarier because it looks like something the military would use(due to the military's need for weapons that last).
Now, if you know nothing about guns, it's an easy call: Ban the AR-15. But if you DO know something about guns, and especially if you are a hunter, you'd know that banning the AR-15 is adjacent to banning the still-more-commonly-used standard rifles, and those aren't able to be modified as easily for the task at hand. It also enables slippery slope arguments to be used pretty effectively, because if you ban the AR-15 -- a weapon that functions the same when fired as any rifle chambered in .223 -- you could just as easily ban said "normal" rifles.
This is why there is so much derision and distrust amongst those who normally would be pushing for stronger restrictions and background checks. It's because, in banning the AR-15, you ban something that functions the same as a rifle they could probably pick up at Walmart for an eighth of the cost.
The better option, I think, would be restricting the types of chambers -- for instance, I'm pretty sure you can fire .223 through a 5.56x45mm chambered rifle, but not the other way around...unless you really like shrapnel, anyway. Reducing the availability of more powerful (read: heavier grain) ammunition would sufficiently limit its effectiveness in...this sort of thing, without doing the same for self-defense or varmint hunting.
.223 is not as powerful, and .308, used for deer hunting, is a powerful round mostly limited to bolt action rifles because of its length, and requirement for accuracy(requiring a longer barrel with different rifling, which also means it's harder to use anywhere in close quarters). Not many AR-15s with a round that powerful, and while they exist, they're also somewhere around 50% and higher more expensive, which limits its demand, too, before you even get to the fact that there's next to no aftermarket parts for them, only proprietary OEM.
On that topic, magazine capacity could also be legislated for rifles alone -- for a .223 rifle, it's possible to use a larger capacity magazine, and the AR-15 itself is no different. Dropping that down to 5 should be sufficient for hunting while also limiting its effectiveness outside of it. Some hunters, I'm sure, will grumble, but it's not drastically reducing their effectiveness. This also neatly ties up an active shooter situation should they be using the literally-any-.223-chambered-rifle-with-extended-magazines that they COULD be using, again, for cheaper than the cheapest AR-15.
