I wish the waders would have an inner inflatable ring around the waist, at the chest level above the belt. That would improve buoyancy and close off the leaks. It seems that would be an easy thing to add to the waders.
Same goes for the jackets. Inflatable pockets should be added to the chest and arm areas of the jacket. Placed correctly the pockets wouldn't even need to be large to keep a person safe.
Several problems especially on the jacket side.
One you need to be face up. Designing that would be tough.
Two you need to have serviceable cartridges. Potentiallyrics this would prevent jackets from working as required in regards to waterproofing. Also would need to seamlessly integrate them into the jacket in several locations, and have pulls. Likely hydrostatic wouldn't work if it was a waterproof jacket.
Three durability on the jacket would be tough. Need to put them in locations that don't have major wear with movement etc.
When worn properly a wading jacket and waders set up is exceedingly watertight. I wasn't even wearing a true wading jacket, just my Columbia titanium with the drawstring tight. Add waders, a belt, and the top drawstring on my simms tightened made for 5-10 seconds of no water when I fell in the Stave (bloody clay) but once that was over very little water entered before I got my footing again. I actually think the water entered at my neck but I'm not sure.