#1, to the OP, I sincerely hope that the USMC is still qualifying with iron sights. I know qualifying with optics when I left ('07) wasn't even an option. Not even remotely discussed as an option to my knowledge.
I do like the ideas of basic soldier skills being required for promotion
While the Marine Corps doesn't require it, promotion to E-4 and E-5 requires you to meet a minimum "cut-in" score. You get points for time in service, time in grade, PFT scores, and rifle qualification scores (along with several other things). So, while basic Marine skills aren't "required" (you can get enough points for time in grade to overcome deficiencies), they are conducive to you making rank in any decent amount of time. The Marine Corps is truly a unique place. I've seen Lcpls (E-3s) tell E-6s of various other MOS's and services what to do. Not in a bossy way, more like a "listen to me and I'll keep your butt alive" way. I've also seen Lcpl squad leaders with a Cpl team leader... rare but it happens.