Also noticed that about half the things on that list are personal preference, and have nothing to do with the successful operation of the rifle
There's a reason the Military has certain specifications for the rifles, Colt and LMT happen to manufacture their rifles to these specs. Many of these specs do however affect the overall durability and reliability of the rifle. Sure, the DPMS is fine for Tom the tool man who puts 50 rounds through his AR every couple of weeks, but for the gentlemen in the sand box gettin' it on, those extra specifications are needed and welcomed.
I sense your agitation with the whole mil-spec thing. Don't worry, I'm not bashing the lesser brands, I'm simply giving out info that may be helpful to others in selecting a rifle. I myself also can not afford a LMT or Colt. However there are certain things in my Stag that I have upgraded. For one, Ive upgraded to an "auto" BCM bolt carrier group. It features a Parkerized exterior and chrome lined inside carrier, machined to
USGI specifications, includes the proper Mil-Spec gas key, gas key is chrome lined and
heat treated per GI specifications, gas key is secured to carrier
via USGI domestic mfg Grade 8 fasteners and properly staked per Mil-Specs.(These properly hardened parts insure a strong staking and proper gas system functioning). The bolt assembly is shot peened for increased strength, includes tool steel machined extractor, BCM Extractor Spring, and is MPI (Magnetic Particle Inspected).
Some of the most common failures on AR's are gas key not properly staked, and broken bolts.