My principle for starting this thread was more predicated on the mid-late 00's having been a sweet spot in the AR world, the industry having jumped the shark a bit since then, and now dialing things back a bit. NOT a call to KISS or Irons only, or "how basic can we make a carbine." THAT will quickly reveal itself to be an exercise in futility once you introduce speed, small targets, and movement.
Case in point, I was all-in on the KISS front from 2004-2011. The pic below was my carbine. All Colt upper, 14.5" M4 barrel on a Colt A2 upper (from a 6520), Colt FA BCG, 18T AAC Phantom pinned/welded by Noveske. It had a VTAC sling, a Trijicon front sight post, and a Surefire M500AB forend light. No fancy triggers to fail, no battery powered optics to fail, simple, reliable, rugged....and SLOW.
I took it to a carbine match expecting to do well and came in almost last. Now, there were some good shooters there and I wasn't nearly as good as I thought I was, but WOW! Turns out things like dot sights and triggers really can enhance performance; especially for a shooter who knows what he's doing. This match had a VTAC barricade, obscured targets, small scoring zones, and no-shoots everywhere. it was NOT your typical 3gn type "blaze a huge piece of cardboard at 7yds" type match.
Now, static shooting, sure you can make irons and stuff work. But, you move, the target moves, you have to go fast, obscured target, etc...you'll do much better with a dot than irons.
But, this thread is more about "more isn't always better past a point." Sure lighter handguards are better, but not at the cost of fragility. LPVO's are nice, but when it's the cost of 3 or 4 Aimpoint micros, and you still have an offset microdot, it's wise to maybe take a step back and see if it really makes the most sense for your use.