You make a lot of valid points about revolvers and their potential use as a home defense weapon. But I think you may have unintentionally exaggerated some characteristics of a couple of weapons.
A revolver is also a good gun to learn on.
Simply because a revolver will not jam.
Unfortunately, revolvers can jam. And if they do, you're not likely to clear the jam with a TRB drill.
They are also inherently heavier than your plastic striker fired auto loaders recommended (GLOCK/M&P/XD). This means less felt recoil and better follow-up shots.
As a general rule, and especially with J-frames, revolvers will have more
felt recoil than a semi-auto -- simply because the rearward movement of the slide absorbs and cushions some of the felt recoil.
However, what about a situation where sending an 8"-10" spread downrange is not ideal.
Unless you have a cylinder choke in that shotgun, an 8"-10" pattern is highly unlikely at a range of 20 feet. With a full choke, at 20 feet, shooting buckshot, all my shotguns produce a pattern of 3-4 inches.