^ This!! I was taught a pre-dive check and very basic dive planning in my SSI OW as well and my instructor did emphasize that you should do it every time, but I hardly ever did one when diving with any group outside a class (some interesting stories as a result of that ...). And it's not just your own gear and safety but your entire team's - last weekend a very vigilant buddy noticed an issue on my rig that I hadn't. Also the part about knowing where your buddy is and knowing that your buddy knows where you are gives me the warm and fuzzies as well. Again, this was taught in my SSI class too but not ingrained in the way GUE did.
Another really important thing I think I would like all OW students to learn is comprehensive gas planning. Reading SB, I know many instructors here are teaching that already but having it be more universal and widespread would be awesome. I dove with a new-to-me buddy a week ago who is also GUE and we mentioned our SCR/DCR during the pre-dive. It's literally 1 phrase but knowing that and because I use the exact same system it meant that, during the dive, I knew almost always what his and my SPGs would read even before asking. This is a super duper great feeling - I don't want to be the buddy who asks for your SPG number every 10min but also kinda sorta want to know what is.
I usually agree wholeheartedly with your posts, but I'm just not persuaded that all agencies should make these things more GUE-like as part of their basic OW course. As you recognize, the problem isn't that students from those other agencies aren't taught pre-dive checks or that instructors don't emphasize them but rather that a lot of students ignore it or are lax about it after getting their cert. The concept of "team" as well--other agencies teach the buddy system, but a lot of students ignore it or become lax about it.
Does PADI really want to add a 10-minute GUE-EDGE (including head-to-toe equipment check) before every dive in a $300 3-day OW class? My PADI instructor taught me the pre-dive check with the BWRAF mnemonic, as many of us were taught, and I think it worked pretty well for most purposes, because I guess I was one of the few who didn't get (too?) lax about it. Where I'm going with this is that I think there will always be people who, by their nature, are inclined to be anal-retentive and love the idea of rigorous checks and people who, by their nature, are inclined to be lax about such things The anal-retentive types gravitate to GUE because it suits them. (GUE could do a better job of marketing Rec 1 to them.) Most Fundies grads probably continue to do a GUE-EDGE, but I'm sure others get lax about it. PADI et al. instructors should already be strenuously emphasizing their existing pre-dive check and the buddy system. I don't think making anything more GUE-like is likely to change post-cert behavior.
With regard to gas planning, I think I read somewhere that it is being emphasized more in OW courses than it was when I took OW. I agree with your sentiment that consumption rate should be taught, but that's hardly a GUE concept. However, I'm not sure that something like Minimum Gas needs to be added. If all divers did just a LITTLE of what we think of as gas planning, they could meet the "back on the boat with 500 psi" standard with no problem. The problem has been that so many divers do NO gas planning at all and, worse yet, don't monitor their gauges (and don't know their consumption rates). So, same thoughts as above. The major agencies are teaching all these things, but most of their students may not be the type who will take this kind of additional detail to heart after the course.
If an agency imports all this good GUE stuff, it just becomes another GUE. Their OW course is going to cost like $750. Would they really want that, or do they want to offer their own flavor of dive training? I don't think GUE is necessarily the pinnacle of dive training. RAID sounds promising. Different strokes for different folks.
