Ditto. I thought long & hard about home defense tools, and settled on a Colt M4LE (as close to a gen-ew-wine M4 as legal for us mere civvies).
From what I can tell, the real problem is the insistence on using “green tip” rounds for soft targets: fragmentation is crucial for 5.56 performance, and the steel-core stuff doesn’t fragment. Use Mk.262 and results are much better. The M16/M4 platform is very sensitive to ammo selection (length & twist vs. weight & velocity, fragmentation velocity, velocity drop vs. distance), and most who have problems with terminal ballistics probably picked the wrong ammo. Feed it a proper diet, and it will perform admirably.
Context is also important. The M4 platform, with its short barrel, is made more for close ranges of urban & CQB situations, not the long ranges of open desert & mountain terrain. For the latter, you want an AR10 or M24 (both .308). Where velocity drops below 2700fps, the M4’s effectiveness plummets (it will still mess up someone’s day, however); compact & light is great for quasi-urban situations, long & heavy works better for reach-out-and-touch-someone.
Upshot: use the right tool for the job. If you don’t, don’t blame the tool.
What we all seek is “over match.” We want to dominate the situations we are likely to find ourselves in if TSHTF. For me, the AR-15 carbine fits this. I can readily tote it in a vehicle or break it down and put it in a pack. A half dozen full magazines would “over match” any gang of pistoleros. The 5.56 will go right through soft armor, but give good terminal effects. Accurate and fast out to 300 yards, or longer if the eyes and optics permit. Light enough to carry all day, though that is unlikely at our ages. I’m not likely to do a 5,000 round unlubed stoppage test, if I ever fire 180 rounds in anger, that will be a max encounter, and I have 100% confidence the rifle will do that and much more.