I'll add my 2 cents as someone with more medical training than backcountry success. There's a difference between "first aid" and "trauma" or life-saving equipment and some of that has been mentioned above. I carry Leukotape wrapped around a piece of a straw for hot spots and its many tape uses, a couple misc bandaids and assorted meds (ibuprofen, imodium, benadryl). Just a few doses of each. Also an extra chapstick because it fits best in there.
Trauma stuff is where people get all worked up. I carry a CAT tourniquet and 1 Israeli style compressed bandage/dressing. I've been trained in their use (if you're not a good youtube video is better than nothing) and am willing to bear the minute weight penalty. You can makeshift a lot of things out of other gear, but a tourniquet isn't one you want to do that with IMO. Or a pressure bandage. Most people live in a fantasy world about "I'll just use my X".
Concerning tourniquets, there is always some new one on the market. Giant zip tie, giant rubber band, whatever. There's a reason the CAT and the SOFT T are the 2 leading tourniquets out there for people who sadly have to use them often: they work. A good windlass tourniquet is the way to go.
Hemostatic gauze or the old powder isn't useless for sure, but I think you'd find more injuries are solved with the other 2 items.
All of my med stuff weighs 8 oz. I'm happy to carry that weight.