As has been said before, tactical refers to one way a gun may be used where as practical describes a gun design that suits it to a particular purpose. Many of the guns described as tactical would not be the first choice of anyone who intends to use the gun for fighting. Lets consider some problems.
The typical magazine fed repeating shotgun is not difficult to load, and speed loading should be part of your training. The addition of a magazine extension causes more problems than it solves. It makes the gun heavier and makes it more likely to run out of ammo when you would prefer it did not. The tendency is to continually stuff additional shells into the magazine that holds only 4 or 5, but a 9 or 10 shot magazine is apt to run dry due to negligence. An empty gun in a gunfight is not a good thing.
There is an interest in the very short shotguns from Dlask, sporting barrels shorter than a foot in length. These guns have two problems that I can see. A 10 round magazine is too much but a 2 round magazine isn't quite enough. The short barrel and forearm might cause a shooter in the heat of combat to extend his support hand forward of the muzzle. An empty gun is bad, but shooting off your hand is worse.
As for attempting to give the shotgun the look of an AR on steroids, I suppose it comes down to personal tastes. It doesn't do much for me, and I don't see the advantage over a conventional stock, but these things sell so there must be folks who see things I don't.
When a shotgun is to be used as a powerful rifle, all sorts of sights can be utilized. I like the ghost ring and post, so that's what is on my gun. A reflex sight or even a low power scope have their place, and under some circumstances are a better choice, but if the gun is to see hard use, I think it is better to keep things simple.
A sling on a shotgun is a good thing. If it is a sling that allows the shooter to use it for support in addition to a carry strap, so much the better.
I do like the looks of a ventilated hand guard on a short barrel shotgun, I don't know why, but ever since I first saw a '97 trench gun, I liked that look. But these things actually have a practical purpose as well. If you train for fighting, that barrel is going to get hot, and the hand guard will protect your hand. Something to consider though is if you take a fall or the gun is dropped, that hand-guard will help protect the barrel.
. The Light switch is the best weapon most will run when the lights come on and if they don't well lets hope that never happens. As I said I personally have no use for a flashlight in a home invasion at MY Place, simplictiy works. 
