I think a shotgun to be a great component of home defense weaponry, but would not want one to be my only HD weapon. When moving through tight spaces, there are ways to mitigate the shotgun's bulk, but not eliminate the issue. I don't like pumping a shotgun when prone; it is a very clumsy thing to have to do.
When I have "cleared" houses and other buildings, as part of my job, with a shotgun, I have only wanted to do it with other trusted, experienced folks working VERY closely with me. (I wear a big-city PD badge, and work nights.) In essence, as the shotgunner inside a structure, I become a specialist, backing up the generalists. Yes, a shotgun can be slung, but a legal-length shotgun hanging on a sling is a very clumsy thing. Best might be the scabbards made for carrying breaching shotguns; I have not used one, myself.
I have cleared a few structures with a 16"-barreled AR15A2 Govt Carbine, and greatly prefer the carbine, if I am going to be moving about with a long gun inside a structure.
When defending a fixed position, with cover and barricades being mostly vertical, a shotgun comes into its own, as a dominating weapon of mass destruction.
Ah, now to the 1911, the best generalist's firearm in the world for battles inside structures, if the shooter has mastered the weapon, IHMO. Among handguns, I love the 1911, second only to a good fighting revolver. Ideally, I would want both of these weapons with me, in a fight inside a structure. On the clock, I actually must carry a different autopistol, a DA .40, by regulation, but in my ideal world, I would move through structures with a 1911, above all other handguns, with a 4" .357 sixgun in reserve. Outdoors, the roles might well switch. No, a .357 fired in a small room will not cause deafness, but I would rather my ears be exposed to a .45 ACP's boom than the sharp crack of a .357 Mag. (I have been exposed to both, unintentionally, when my hearing protection was not in place.)