I really like your train of thought here Gabe. I have seen numerous recent studies on type 2 diabetics showing that those that can adhere a lower carb or even keto style diet can reduce or even stop their need of insulin. Obviously this is displaying an enormous increase in sensitivity to the hormone. And also as you pointed out, as someone heads more toward the "endomorph" phenotype or has increasting central adiposity, insulin sensitivity decreases.
Not to get off topic, but I really think you opened a can of worms here because this is really where I see or feel the USDA guidelines should be heading. The average person is still pushed for 45-65% of their calories from carbohydrate each day, with our average activity levels and metabolic profiles as a society I think these recommendations are obscene.
Now back to my previous train of thought hah.... I like your attack plan for the problem, I totally agree that increasing sensitivity to these hormones should be top priority. In my perspective the plan for an overweight bodybuilder/athlete and just a normal overweight person though would differ dramatically since there are many other confounding factors involved. (for example a bodybuilder would likely be driven, therefore would be more apt to deal with food cravings, the average individual may need keto (since satiety is usually greater) to stay on track).
The only thing I think I would add would be nutrigenomic aides like ALA, cinnamon, maybe a few others as they can have a pretty profound effect on insulin sensitivity (especially ALA).
I feel like I could have wrote for days on this but I know there will be great responses for me to reply to hah so I'll stop here