If I were single, then I would consider my 870. But I'm not. My wife is a smaller person. She is capable and confidant with a light weight AR. She wants nothing to do with a 12 gage 870. So I have an AR with a white light located within the bedroom. It would take about 30 seconds to unlock and obtain. The home defense long gun has to work for every adult that may be in the household, not just me. So an AR is what is available.
The AR is for known threats in a static defense. The handgun with a WML is for unknown potential threats. For example, I hear a noise only to find one of the Step-Kids came back from college and is trying to be quiet so as to not wake up anyone. I hear signs of a forced entry, then it's a bit different response.
I keep a handgun with a WML staged in the bedroom. The, "pants on the floor with a holster attached" may work for me, but not so much for the wife if I am not at home at the time.
I also keep a smaller 9mm stashed on the first floor of the house. This is in case the wife or one of the adult kids are on the first floor when an issue occurs.
We tend to want to talk about hardware (guns) on firearm forums, when discussing home defense. Not saying that's a bad thing. But personally, I look at home defense as a layered approach. The layered approach would include things like outside lighting and keeping shrubs at bay so as to deny suspects concealment prior to forcing entry. Hardening the exterior with solid doors and real locks. A dog, preferable one that barks at strangers. All these things give us time to assess the situation and react.
I view a long gun as an option in my home defense plan. Depending on the situation, I may or may not grab the long gun. But it is definitely something I want as an option.