Re. carrying stuff - the actual quantity is pretty non-negotiable, I presume (I'm an ex mountaineer, and had a similar issue - you may weigh 30% less than a bloke, you may be less strong than a bloke - but you still need a rope, climbing equipment, axes and crampons. And the "women need less water and this will make a difference to pack weight" theory is... well, laughable is the first thought that comes to my mind).
But yes, lots of room for ergonomic improvements. It's not just back length, it's pelvic girdle size in relation to back length, it's shoulder anatomy, it's a whole range of things. Mountaineering packs have come in men's and women's for decades (though personally I frequently find a man's frame suits my shape better). Also body armour is an ongoing scandal in both the armed forces and the police (stories of women officers requesting breast reductions simply because they cannot get stab vests to fit them).
A female friend of mine was in the RAF and got invalided out with stress fractures among other things. She commented "I always wondered, back when I was a cadet, why female officers were built like brick shithouses, and now I know".
(Disclaimer, I also have an ex-Navy female friend who was very petite - but of the wiry whippet build with surprising strength and immense stamina).
My sympathies on the boots issue too - that's another ongoing scandal in the forces. The standard issue boots are simply not fit for purpose, they're appalling, so soldiers are having to buy decent boots out of their own money.