The current problem with composites is the difficulty of identifying internal cracking/crazing (or whatever). One phase of testing includes thumping on the suspect part like its a watermelon. Perhaps better non-destructible methods now exist--but I am not keen to see aircraft careening across the landscape/skyscape because of rudder or other control surface failure.
New materials are being produced that are lighter than aluminum and stronger than steel, and I don't mean titanium.
Carbon-graphite, carbon-composite,carbon-fiberglass are what is being discussed, and are old technology. Car bodies, Kite frames, RC planes, boats, all of these use that technology.
Some of this is obviously going into rebuild of our current airframes.
But, there is newer technology coming soon.